chore: .NET 9 build fixes

Fix a JSON trimmer error:

	src/Uno.Extensions.Authentication.MSAL/MsalAuthenticationProvider.cs(249,52): error IL2026:
	  Using member 'System.Text.Json.JsonSerializer.Serialize<TValue>(TValue, JsonSerializerOptions)' which has 'RequiresUnreferencedCodeAttribute' can break functionality when trimming application code.
	  JSON serialization and deserialization might require types that cannot be statically analyzed. Use the overload that takes a JsonTypeInfo or JsonSerializerContext, or make sure all of the required types are preserved.

Update `MsalAuthenticationProvider.cs` to use `System.Text.Json`
[Source Generators][0].

"Fix" or otherwise silence trimmer errors (?!):

	uno.extensions/src/Uno.Extensions.Hosting.UI/UnoHost.cs(105,42): error IL2026:
	  Using member 'Microsoft.Extensions.DependencyInjection.OptionsConfigurationServiceCollectionExtensions.Configure<TOptions>(IServiceCollection, IConfiguration)' which has 'RequiresUnreferencedCodeAttribute' can break functionality when trimming application code.
	  TOptions's dependent types may have their members trimmed.
	  Ensure all required members are preserved.

In this case I'm not sure what the correct fix *is*, so use
`[UnconditionalSuppressMessage]` to silence the underlying warning.

	src/Uno.Extensions.Navigation.UI/RouteResolverDefault.cs(261,11): error IL2026:
	  Using member 'System.Reflection.Assembly.GetTypes()' which has 'RequiresUnreferencedCodeAttribute' can break functionality when trimming application code.
	  Types might be removed.

Add `[RequiresUnreferencedCode]` to `AssemblyExtensions.SafeGetTypes()`
and `RouteResolverDefault.LoadedTypes` (calls `.SafeGetTypes()`), then
use `[UnconditionalSuppressMessage]` to "limit the contagion" of the
`[RequiresUnreferencedCode]` on `.LoadedTypes`.

[0]: https://learn.microsoft.com/en-us/dotnet/standard/serialization/system-text-json/source-generation

Author: jonpryor

src/Uno.Extensions.Authentication.MSAL/MsalAuthenticationProvider.cs

@@ -4,6 +4,9 @@
 using Uno.Extensions.Logging;
 using LogLevel = Microsoft.Extensions.Logging.LogLevel;
 #if UNO_EXT_MSAL
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using System.Text.Json.Serialization.Metadata;
 using MsalCacheHelper = Microsoft.Identity.Client.Extensions.Msal.MsalCacheHelper;
 #endif
 
@@ -246,7 +249,7 @@ private ValueTask<AuthenticationResult> AcquireInteractiveTokenAsync(IDispatcher
 		try
 		{
 			Logger.LogInformation("Attempting to perform silent sign in . . .");
-			Logger.LogInformation($"Authentication Scopes: {JsonSerializer.Serialize(_scopes)}");
+			Logger.LogInformation($"Authentication Scopes: {ToJson(_scopes)}");
 
 			Logger.LogInformation($"Account Name: {firstAccount.Username}");
 
@@ -268,5 +271,24 @@ private ValueTask<AuthenticationResult> AcquireInteractiveTokenAsync(IDispatcher
 
 		return default;
 	}
+
+	static string? ToJson (string[]? values)
+	{
+		if (values == null)
+		{
+			return null;
+		}
+
+		return JsonSerializer.Serialize(values, StringArrayJsonSerializerContext.Default.StringArray);
+	}
+
 #endif
 }
+
+#if UNO_EXT_MSAL
+[JsonSourceGenerationOptions]
+[JsonSerializable(typeof(string[]))]
+internal sealed partial class StringArrayJsonSerializerContext : JsonSerializerContext
+{
+}
+#endif  // UNO_EXT_MSAL

src/Uno.Extensions.Hosting.UI/UnoHost.cs

@@ -1,4 +1,6 @@
-namespace Uno.Extensions.Hosting;
+using System.Diagnostics.CodeAnalysis;
+
+namespace Uno.Extensions.Hosting;
 
 /// <summary>
 /// Contains helpers to create a HostBuilder that is tailored to multiple target platforms.
@@ -59,7 +61,7 @@ public static IHostBuilder CreateDefaultBuilder(Assembly applicationAssembly, st
 	{
 		PlatformHelper.SetAppAssembly(applicationAssembly);
 		applicationAssembly = PlatformHelper.GetAppAssembly()!;
-		return new HostBuilder()
+		var builder = new HostBuilder()
 			.ConfigureCustomDefaults(args)
 			.ConfigureAppConfiguration((ctx, appConfig) =>
 			{
@@ -102,7 +104,15 @@ public static IHostBuilder CreateDefaultBuilder(Assembly applicationAssembly, st
 						config.AddInMemoryCollection(queryDict);
 					}
 				})
-			.ConfigureServices((ctx, services) => services.Configure<HostConfiguration>(ctx.Configuration.GetSection(nameof(HostConfiguration))))
 			.UseStorage();
+		return ConfigureHostConfigurationServices(builder);
+
+		[UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "🤷‍♂️")]
+		static IHostBuilder ConfigureHostConfigurationServices(IHostBuilder builder)
+		{
+			builder
+				.ConfigureServices((ctx, services) => services.Configure<HostConfiguration>(ctx.Configuration.GetSection(nameof(HostConfiguration))));
+			return builder;
+		}
 	}
 }

src/Uno.Extensions.Navigation.UI/RouteResolverDefault.cs

@@ -1,4 +1,5 @@
-using System.Reflection;
+using System.Diagnostics.CodeAnalysis;
+using System.Reflection;
 
 namespace Uno.Extensions.Navigation;
 
@@ -160,14 +161,14 @@ private RouteInfo[] DefaultMapping(string? path = null, Type? view = null, Type?
 			return default;
 		}
 
-		if (allowMatchExact && LoadedTypes.TryGetValue(path, out var type))
+		if (allowMatchExact && TryGetLoadedType(path, out var type))
 		{
 			return type;
 		}
 
 		foreach (var suffix in suffixes)
 		{
-			if (LoadedTypes.TryGetValue($"{path}{suffix}", out type))
+			if (TryGetLoadedType($"{path}{suffix}", out type))
 			{
 				if (condition?.Invoke(type) ?? true)
 				{
@@ -179,6 +180,12 @@ private RouteInfo[] DefaultMapping(string? path = null, Type? view = null, Type?
 			Logger.LogWarningMessage($"Navigation failed: Could not resolve type for path '{path}'.");
 
 		return null;
+
+		[UnconditionalSuppressMessage("Trimming", "IL2026", Justification = "LoadedTypes has the message; suppress use to limit contagion.")]
+		bool TryGetLoadedType(string path, [NotNullWhen (true)] out Type? type)
+        {
+            return LoadedTypes.TryGetValue(path, out type);
+        }
 	}
 
 	private string PathFromTypes(Type? view, Type? viewModel)
@@ -235,6 +242,7 @@ private string TrimSuffices(string? path, IEnumerable<string> suffixes)
 
 	public IDictionary<string, Type> LoadedTypes
 	{
+		[RequiresUnreferencedCode("From Assembly.GetTypes(): Types might be removed")]
 		get
 		{
 			if (loadedTypes is null)
@@ -254,6 +262,8 @@ where t.IsClass
 public static class AssemblyExtensions
 {
 	public static IList<string> Excludes { get; } = new List<string>();
+
+	[RequiresUnreferencedCode("From Assembly.GetTypes(): Types might be removed")]
 	public static Type[] SafeGetTypes(this Assembly assembly)
 	{
 		try