Fix Xamarin assembly names in HttpClientHandler (#64391)

Update to match the new names from dotnet/macios#13847

Co-authored-by: Alexander Köplinger <alex.koeplinger@outlook.com>

Author: github-actions[bot]

src/libraries/System.Net.Http/src/System/Net/Http/HttpClientHandler.AnyMobile.InvokeNativeHandler.cs

@@ -21,16 +21,16 @@ public partial class HttpClientHandler : HttpMessageHandler
         private const string GetHttpMessageHandlerType = "Android.Runtime.AndroidEnvironment, Mono.Android";
 #elif TARGET_IOS
         private const string NativeHandlerType = "System.Net.Http.NSUrlSessionHandler";
-        private const string AssemblyName = "Xamarin.iOS";
-        private const string GetHttpMessageHandlerType = "ObjCRuntime.RuntimeOptions, Xamarin.iOS";
+        private const string AssemblyName = "Microsoft.iOS";
+        private const string GetHttpMessageHandlerType = "ObjCRuntime.RuntimeOptions, Microsoft.iOS";
 #elif TARGET_MACCATALYST
         private const string NativeHandlerType = "System.Net.Http.NSUrlSessionHandler";
-        private const string AssemblyName = "Xamarin.MacCatalyst";
-        private const string GetHttpMessageHandlerType = "ObjCRuntime.RuntimeOptions, Xamarin.MacCatalyst";
+        private const string AssemblyName = "Microsoft.MacCatalyst";
+        private const string GetHttpMessageHandlerType = "ObjCRuntime.RuntimeOptions, Microsoft.MacCatalyst";
 #elif TARGET_TVOS
         private const string NativeHandlerType = "System.Net.Http.NSUrlSessionHandler";
-        private const string AssemblyName = "Xamarin.TVOS";
-        private const string GetHttpMessageHandlerType = "ObjCRuntime.RuntimeOptions, Xamarin.TVOS";
+        private const string AssemblyName = "Microsoft.tvOS";
+        private const string GetHttpMessageHandlerType = "ObjCRuntime.RuntimeOptions, Microsoft.tvOS";
 #else
 #error Unknown target
 #endif