[ios] test MemoryAnalyzers package

Context: https://github.com/jonathanpeppers/memory-analyzers
Context: https://www.nuget.org/packages/MemoryAnalyzers/0.1.0-beta.1

This adds a new Roslyn analyzer that warns about the following cases.

 ## MA0001

Don't define `public` events in `NSObject` subclasses:

```csharp
public class MyView : UIView
{
    // NOPE!
    public event EventHandler MyEvent;
}
```

 ## MA0002

Don't declare members in `NSObject` subclasses unless they are:

* `WeakReference` or `WeakReference<T>`
* Value types

```csharp
class MyView : UIView
{
    // NOPE!
    public UIView? Parent { get; set; }

    public void Add(MyView subview)
    {
        subview.Parent = this;
        AddSubview(subview);
    }
}
```

 ## MA0003

Don't subscribe to events inside `NSObject` subclasses unless:

* It's your event via `this.MyEvent` or from a base type.
* The method is `static`.

```csharp
class MyView : UIView
{
    public MyView()
    {
        var picker = new UIDatePicker();
        AddSubview(picker);
        picker.ValueChanged += OnValueChanged;
    }

    void OnValueChanged(object sender, EventArgs e) { }

    // Use this instead and it doesn't leak!
    //static void OnValueChanged(object sender, EventArgs e) { }
}
```

This is also on NuGet, but I just commited the package until we can get
it added to the `dotnet-public` feed.

I've marked a couple places OK, but `Core.csproj` will currently be at:

    [src\Core\src\Core.csproj::TargetFramework=net7.0-ios]
    32 Error(s)

src/Core/src/Core.csproj

@@ -15,6 +15,7 @@
   <Import Project="$(MauiSrcDirectory)MultiTargeting.targets" />
 
   <ItemGroup>
+    <PackageReference Include="MemoryAnalyzers" Version="0.1.0-beta.1" />
     <PackageReference Include="Microsoft.Extensions.Configuration" />
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" />
     <PackageReference Include="Microsoft.Extensions.Logging" />

src/Core/src/Platform/iOS/MauiImageView.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
 using CoreGraphics;
 using ObjCRuntime;
 using UIKit;
@@ -31,6 +32,7 @@ public override void MovedToWindow()
 		}
 
 		[Obsolete("Use IImageHandler.OnWindowChanged() instead.")]
+		[UnconditionalSuppressMessage("Memory", "MA0001", Justification = "Completely unused, deprecated")]
 		public event EventHandler? WindowChanged
 		{
 			add { }

src/Core/src/Platform/iOS/MauiUIApplicationDelegate.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
 using Foundation;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Maui.Hosting;
@@ -149,6 +150,7 @@ public virtual void PerformFetch(UIApplication application, Action<UIBackgroundF
 			Services?.InvokeLifecycleEvents<iOSLifecycle.PerformFetch>(del => del(application, completionHandler));
 		}
 
+		[UnconditionalSuppressMessage("Memory", "MA0002", Justification = "There can only be one MauiUIApplicationDelegate.")]
 		public static MauiUIApplicationDelegate Current { get; private set; } = null!;
 
 		[Export("window")]

src/Core/src/Platform/iOS/MauiWKWebView.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Drawing;
 using System.IO;
 using System.Threading.Tasks;
@@ -12,6 +13,7 @@ namespace Microsoft.Maui.Platform
 {
 	public class MauiWKWebView : WKWebView, IWebViewDelegate
 	{
+		[UnconditionalSuppressMessage("Memory", "MA0002", Justification = "Used to persist cookies across WebView instances. Not a leak.")]
 		static WKProcessPool? SharedPool;
 
 		string? _pendingUrl;

src/Core/src/Platform/iOS/WrapperView.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics.CodeAnalysis;
 using CoreAnimation;
 using CoreGraphics;
 using Microsoft.Maui.Graphics;
@@ -12,6 +13,7 @@ public partial class WrapperView : UIView, IDisposable
 		CAShapeLayer? _maskLayer;
 		CAShapeLayer? _backgroundMaskLayer;
 		CAShapeLayer? _shadowLayer;
+		[UnconditionalSuppressMessage("Memory", "MA0002", Justification = "_borderView is a SubView")]
 		UIView? _borderView;
 
 		public WrapperView()