[clr-ios] Enable telemetry on CoreCLR mobile platforms

[kotlarmilos]

Description

Add telemetry to collect data on CoreCLR usage on Apple mobile platforms.

Tasks

• Validate presence of UseMonoRuntime metadata in .NET SDK telemetry for Build and Publish events
• Add runtime metadata flag to VS Code extension telemetry
  • Might not be needed if VS Code extension uses .NET SDK directly as the telemetry would be already included in SDK telemetry)
• Add build-time telemetry hooks for Apple mobile
  • Investigate what metadata is stored in existing .NET SDK and VS Code extension telemetry, extend if necessary

[dotnet-policy-service]

Tagging subscribers to this area: @agocke, @dotnet/runtime-infrastructure
See info in area-owners.md if you want to be subscribed.

[dotnet-policy-service]

Tagging subscribers to 'os-ios': @vitek-karas, @kotlarmilos, @steveisok, @akoeplinger
See info in area-owners.md if you want to be subscribed.

[dotnet-policy-service]

Tagging subscribers to 'arch-android': @vitek-karas, @simonrozsival, @steveisok, @akoeplinger
See info in area-owners.md if you want to be subscribed.

[kotlarmilos]

Add build-time telemetry hooks for Apple mobile

In PR

Add runtime metadata flag to VS Code extension telemetry

VS Code is using .NET SDK which should trigger the existing build and publish telemetry