[Blazor] WebAssembly OpenTelemetry integration

[javiercn]

Summary

Enable comprehensive OpenTelemetry support in Blazor WebAssembly for Aspire integration, including metrics, tracing, and logging instrumentation.

Background

Blazor WebAssembly currently lacks full OpenTelemetry support needed for Aspire integration. This requires developers to manually configure multiple components:

1. MSBuild properties - MetricsSupport and EventSourceSupport must be manually enabled in .csproj for runtime instrumentation to work
2. Component telemetry - Blazor's built-in metrics and tracing aren't registered by default on the WebAssembly host
3. Configuration access - OTEL settings from environment variables need to be accessible through IConfiguration

This work enables OpenTelemetry to function properly in Blazor WebAssembly with minimal manual setup.