Recognize roslyn telemetry

[jjonescz]

Roslyn counterpart: dotnet/roslyn#84725

[azure-pipelines]

Azure Pipelines:
Successfully started running 1 pipeline(s).
2 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[dotnet-policy-service]

This PR has been labeled with Area-Telemetry. Please ensure that any telemetry changes in this PR

• comply with the published guidance * are added to the repo-local telemetry documentation * get a matching .NET Docs issue raised to document the telemetry changes
  • Go to https://learn.microsoft.com/dotnet/core/tools/telemetry
  • Scroll down to the bottom and click the 'Open a documentation issue' link to create an issue with pre-filled details

[azure-pipelines]

Azure Pipelines:
Successfully started running 1 pipeline(s).
2 pipeline(s) were filtered out due to trigger conditions.
There may be pipelines that require an authorized user to comment /azp run to run.

[Copilot]

Pull request overview

Adds recognition/forwarding of the new Roslyn compiler cache telemetry event from MSBuild into the dotnet CLI telemetry pipeline, aligning with the Roslyn-side telemetry emission.

Changes:

• Allowlist and forward the roslyn/compilercache MSBuild telemetry event via MSBuildLogger.FormatAndSend.
• Add a dotnet.Tests regression test verifying the event is forwarded with the expected msbuild/ prefix and properties.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
test/dotnet.Tests/CommandTests/MSBuild/GivenMSBuildLogger.cs	Adds a test ensuring the Roslyn compiler cache telemetry event is forwarded.
src/Cli/dotnet/Commands/MSBuild/MSBuildLogger.cs	Adds the Roslyn compiler cache telemetry event name and forwards it via the MSBuild telemetry allowlist.