Update to .NET 10 (#19869)

* Update to .NET 10 and C# 14

* Remove reflection usage in AvaloniaAccessHelper

* Fix Android nullability errors

* Fix WindowMetrics.WindowInsets removed from AndroidX

* Update pipelines

* Fix ValidateApiDiff for missing frameworks

* Fix Windows integration tests

* Update Xamarin.AndroidX.Window to 1.5.0

* Fix MacCatalyst supported version

* Remove unused Xunit.Extensions.Ordering

* Try to fix macOS integration tests

* Update pipeline runner to macOS 15

* Disable LeakTests

* Fix .NET Framework unit tests

* Fix BuildTests

* Bump minimum Android API level to 24

* Update to .NET 10 RTM

* Update XamlX

* update android insets and activity code to handle deprecated behaviors in api 36

---------

Co-authored-by: Emmanuel Hansen <emmausssss@gmail.com>

Directory.Build.props

@@ -8,7 +8,7 @@
       <!-- https://github.com/dotnet/msbuild/issues/2661 -->
       <AddSyntheticProjectReferencesForSolutionDependencies>false</AddSyntheticProjectReferencesForSolutionDependencies>
       <RunApiCompat>False</RunApiCompat>
-      <LangVersion>12</LangVersion>
+      <LangVersion>14.0</LangVersion>
       <CreateHardLinksForCopyAdditionalFilesIfPossible>true</CreateHardLinksForCopyAdditionalFilesIfPossible>
       <CreateHardLinksForCopyFilesToOutputDirectoryIfPossible>true</CreateHardLinksForCopyFilesToOutputDirectoryIfPossible>
       <CreateHardLinksForCopyLocalIfPossible>true</CreateHardLinksForCopyLocalIfPossible>