Enable OpenTelemetry metrics and tracing for MAUI in Service Defaults (#31900)

* Enable OpenTelemetry metrics and tracing for MAUI

Added support for OpenTelemetry metrics and tracing from the .NET MAUI SDK.

* Update src/Templates/src/templates/maui-aspire-servicedefaults/Extensions.cs

Co-authored-by: Copilot <[email protected]>

---------

Co-authored-by: Copilot <[email protected]>

Author: jfversluis

src/Templates/src/templates/maui-aspire-servicedefaults/Extensions.cs

@@ -52,12 +52,18 @@ public static TBuilder ConfigureOpenTelemetry<TBuilder>(this TBuilder builder) w
 
         builder.Services.AddOpenTelemetry()
             .WithMetrics(metrics =>
-            {                
+            {
+                // Enable reporting metrics coming from the .NET MAUI SDK
+                metrics.AddMeter("Microsoft.Maui");
+                
                 metrics.AddHttpClientInstrumentation()
                     .AddRuntimeInstrumentation();
             })
             .WithTracing(tracing =>
             {
+                // Enable reporting tracing coming from the .NET MAUI SDK
+                tracing.AddSource("Microsoft.Maui");
+                
                 tracing.AddSource(builder.Environment.ApplicationName)
                     // Uncomment the following line to enable gRPC instrumentation (requires the OpenTelemetry.Instrumentation.GrpcNetClient package)
                     //.AddGrpcClientInstrumentation()