Fix `dotnetup` telemetry with new otel platform + dashb

[nagilson]

Summary

The current dotnetup telemetry implementation uses a temporary/personal App Insights connection key. This needs to be replaced with the official SDK CLI telemetry endpoint once the SDK's migration to OpenTelemetry is complete.

Background

dotnetup telemetry was implemented using OpenTelemetry with Azure Monitor exporter ahead of the main SDK CLI telemetry migration. The current connection key is a placeholder that should NOT be used in production.

Blocked By

This work is blocked by the SDK CLI's migration to OpenTelemetry:

• Replace ApplicationInsights dependency with OpenTelemetry libraries #49668 - Replace ApplicationInsights dependency with OpenTelemetry libraries (assigned to @MiYanni)

Action Items

• Wait for SDK CLI OTel migration to be completed
• Obtain the official production Azure Monitor connection string from the SDK telemetry team
• Update DotnetupTelemetry.cs to use the official connection string
• Validate telemetry is flowing to the correct endpoint
• Remove any dev/test telemetry data from temporary endpoint

Notes

Since dotnetup is currently on a dev branch (release/dnup) and not yet shipping, using the temporary connection key is acceptable for development and testing purposes.

Related

• PR: Add quality metrics for dotnetup  nagilson/sdk#10
• SDK OTel Epic: Enable the dotnet CLI to be shipped as a Native AOT application #49667

[nagilson]

this is done but its not working because we dont send the data in the data x platform format