refactor(instrumentation-grpc): fix eslint warnings

```
/home/runner/work/opentelemetry-js/opentelemetry-js/experimental/packages/opentelemetry-instrumentation-grpc/src/clientUtils.ts
  105:42  warning  Unexpected any. Specify a different type  @typescript-eslint/no-explicit-any

/home/runner/work/opentelemetry-js/opentelemetry-js/experimental/packages/opentelemetry-instrumentation-grpc/src/instrumentation.ts
  129:69  warning  Unexpected any. Specify a different type  @typescript-eslint/no-explicit-any
  134:69  warning  Unexpected any. Specify a different type  @typescript-eslint/no-explicit-any
  139:68  warning  Unexpected any. Specify a different type  @typescript-eslint/no-explicit-any
  144:68  warning  Unexpected any. Specify a different type  @typescript-eslint/no-explicit-any

/home/runner/work/opentelemetry-js/opentelemetry-js/experimental/packages/opentelemetry-instrumentation-grpc/src/serverUtils.ts
  112:23  warning  Don't use `Function` as a type  @typescript-eslint/ban-types
  152:23  warning  Don't use `Function` as a type  @typescript-eslint/ban-types
  207:31  warning  Don't use `Function` as a type  @typescript-eslint/ban-types
  211:31  warning  Don't use `Function` as a type  @typescript-eslint/ban-types

/home/runner/work/opentelemetry-js/opentelemetry-js/experimental/packages/opentelemetry-instrumentation-grpc/test/helper.ts
  83:11  warning  Don't use `Function` as a type  @typescript-eslint/ban-types
```

This commit does not involve any changes to runtime code and can
be safely merged without any concerns about changing behavior.

The first can be replaced with the more precise type that we are
expecting.

The second just wansn't needed anymore.

The third is highly unusual. After spending significant amount of
time reading and stepping through the code – I am quite confident
that the `.call({}, ...)` (and `.apply({}, ...)` elsewhere in the
tests) are a mistake that we inherited from very old code. However
I don't feel confident enough that I can *explain* what is going
on here to make a change to the runtime code, so in the meantime,
I think the best course of action is to leave it as-is, document
the issue and have someone with more expertise untangle this down
the road.

The last one was a change in test code to use a more precise call
signature.

Ref #5365

experimental/packages/opentelemetry-instrumentation-grpc/src/clientUtils.ts

@@ -102,7 +102,7 @@ export function patchResponseMetadataEvent(
   call: EventEmitter,
   metadataCapture: metadataCaptureType
 ) {
-  call.on('metadata', (responseMetadata: any) => {
+  call.on('metadata', (responseMetadata: Metadata) => {
     metadataCapture.client.captureResponseMetadata(span, responseMetadata);
   });
 }

experimental/packages/opentelemetry-instrumentation-grpc/src/instrumentation.ts

@@ -126,22 +126,22 @@ export class GrpcInstrumentation extends InstrumentationBase<GrpcInstrumentation
           this._wrap(
             moduleExports.Client.prototype,
             'makeUnaryRequest',
-            this._patchClientRequestMethod(moduleExports, false) as any
+            this._patchClientRequestMethod(moduleExports, false)
           );
           this._wrap(
             moduleExports.Client.prototype,
             'makeClientStreamRequest',
-            this._patchClientRequestMethod(moduleExports, false) as any
+            this._patchClientRequestMethod(moduleExports, false)
           );
           this._wrap(
             moduleExports.Client.prototype,
             'makeServerStreamRequest',
-            this._patchClientRequestMethod(moduleExports, true) as any
+            this._patchClientRequestMethod(moduleExports, true)
           );
           this._wrap(
             moduleExports.Client.prototype,
             'makeBidiStreamRequest',
-            this._patchClientRequestMethod(moduleExports, true) as any
+            this._patchClientRequestMethod(moduleExports, true)
           );
           return moduleExports;
         },

experimental/packages/opentelemetry-instrumentation-grpc/src/serverUtils.ts

@@ -108,7 +108,10 @@ function serverStreamAndBidiHandler<RequestType, ResponseType>(
     endSpan();
   });
 
-  // Types of parameters 'call' and 'call' are incompatible.
+  // TODO: Investigate this call/signature – it was inherited from very old
+  // code and the `this: {}` is highly suspicious, and likely isn't doing
+  // anything useful. There is probably a more precise cast we can do here.
+  // eslint-disable-next-line @typescript-eslint/ban-types
   return (original as Function).call({}, call);
 }
 
@@ -149,6 +152,11 @@ function clientStreamAndUnaryHandler<RequestType, ResponseType>(
   };
 
   context.bind(context.active(), call);
+
+  // TODO: Investigate this call/signature – it was inherited from very old
+  // code and the `this: {}` is highly suspicious, and likely isn't doing
+  // anything useful. There is probably a more precise cast we can do here.
+  // eslint-disable-next-line @typescript-eslint/ban-types
   return (original as Function).call({}, call, patchedCallback);
 }
 
@@ -204,10 +212,18 @@ export function handleUntracedServerFunction<RequestType, ResponseType>(
     case 'unary':
     case 'clientStream':
     case 'client_stream':
+      // TODO: Investigate this call/signature – it was inherited from very old
+      // code and the `this: {}` is highly suspicious, and likely isn't doing
+      // anything useful. There is probably a more precise cast we can do here.
+      // eslint-disable-next-line @typescript-eslint/ban-types
       return (originalFunc as Function).call({}, call, callback);
     case 'serverStream':
     case 'server_stream':
     case 'bidi':
+      // TODO: Investigate this call/signature – it was inherited from very old
+      // code and the `this: {}` is highly suspicious, and likely isn't doing
+      // anything useful. There is probably a more precise cast we can do here.
+      // eslint-disable-next-line @typescript-eslint/ban-types
       return (originalFunc as Function).call({}, call);
     default:
       break;

experimental/packages/opentelemetry-instrumentation-grpc/test/helper.ts

@@ -80,7 +80,7 @@ type TestGrpcClient = Client & {
 interface TestGrpcCall {
   description: string;
   methodName: string;
-  method: Function;
+  method: (...args: any[]) => unknown;
   request: TestRequestResponse | TestRequestResponse[];
   result: TestRequestResponse | TestRequestResponse[];
   metadata?: Metadata;