`System/Collections` must not appear in JNI method signatures

### Android framework version

net8.0-android, net9.0-android, Other

### Affected platform version

All

### Description

The string `LSystem/Collections` *must not appear* within JNI Method Signatures, because that is not the beginning of a valid Java type.

The current offender:

https://github.com/dotnet/android-libraries/blob/8305dd036a12c9a0ac5ef4c6c35c8dd373b037c1/source/androidx.media3/media3-exoplayer/Additions/AndroidX.Media3.ExoPlayer.IExoPlayer.cs#L34

The fact that such methods are mentioned in a `Transforms.xml` is also not encouraging:

https://github.com/dotnet/android-libraries/blob/8305dd036a12c9a0ac5ef4c6c35c8dd373b037c1/source/androidx.media3/media3-exoplayer/Transforms/Metadata.xml#L7-L14

JNI method signatures must only reference Java types. Failure to do so means the Java method cannot be resolved at runtime, which will result in [exceptions at runtime](https://discord.com/channels/732297728826277939/732297837953679412/1336845663706812487):

> @ne0rrmatrix: It looks like in Media3 `SetMediaItems` and `AddMediaItems` is not working.
>
> Java.Lang.NoSuchMethodError: 'no non-static method "Landroidx/media3/exoplayer/ExoPlayerImpl;.setMediaItems(LSystem/Collections/Generic/IList;)V"'

### Relevant log output

```shell

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