Remove _RemoveAppAssemblyFromTrimmerRoots workaround once SDK contains dotnet/runtime#125673 #11146

src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.Trimmable.CoreCLR.targets contains a temporary _RemoveAppAssemblyFromTrimmerRoots target (added in #11144) that removes @(IntermediateAssembly) from @(TrimmerRootAssembly) to avoid IL1034 during trimmable typemap builds.

The upstream fix in dotnet/runtime#125673 makes this unnecessary: once the consumed .NET SDK's Microsoft.NET.ILLink.targets contains the '$(OutputType)' != 'Library' condition on the TrimmerRootAssembly Include, the item is never added for Android projects (which force OutputType=Library) in the first place.

Action items

1. Verify the SDK flow-in has landed (check Microsoft.NET.ILLink.targets in the bundled SDK for the new condition).
2. Delete the _RemoveAppAssemblyFromTrimmerRoots target and its comment from Microsoft.Android.Sdk.TypeMap.Trimmable.CoreCLR.targets.
3. Run tests/Microsoft.Android.Sdk.TrimmableTypeMap.Tests and a CoreCLRTrimmable Mono.Android.NET-Tests device run to confirm trimming still works without the workaround.