No error occurs if executing "Azure Blob Storage Trigger (using Event Grid)" function with an invalid request body

[v-ruizh]

OS: All
Build Version: 20241216.1
Regression: Not a Regression

Repro Steps:

1. Create a JavaScript project with "Azure Blob Storage Trigger (using Event Grid)" template.
2. Create a Node.js function app.
3. Deploy the JavaScript project to the above function app.
4. Expand the function app -> Expand the Functions node -> Right click the function and select "Execute Function Now..." -> Enter an invalid request body to execute.
5. Check whether fails to execute the function with an error.

Expect:
Fail to execute the function with an error.

Actual:
No error occurs.

[nturinski]

Because Flex Function apps no longer use storage accounts for blob storage triggers, we are supposed to trigger it using event grid. Needs to investigate how we would mock this locally.