Copilot-specific env variable for running commands

[Youssef1313]

Can Copilot run all commands with some special env variable? There are already some env vars available today under some situations (see https://github.com/dotnet/sdk/blob/1e5d8e39d3026edb222cdf4f8d8240f1eb99f24b/src/Cli/dotnet/Telemetry/LLMEnvironmentDetectorForTelemetry.cs), but looks like Copilot in VSCode doesn't use any special env variable.

This helps tooling around to provide better output from commands.

[meganrogge]

What's your use case?

[Youssef1313]

1. For .NET SDK and MSBuild, it can disable terminal logger or ANSI output which makes it easier for LLMs to understand the output.
2. For .NET testing (Microsoft.Testing.Platform, to be specific), we can also disable ANSI output in LLM environments.