dotnet trace collect-linux usability issues

[hoyosjs]

During investigations we've noticed a few usability issues.

• When the user provides a host namespace PID to trace a process running inside a container, dotnet-trace can't resolve the diagnostic server socket created by the app in the container. This is tracked by [dotnet-trace][collect-linux] Unable to specifically trace a cross-container process #5694

• When the user provides a host namespace PID to trace a process running inside a container, the library that backs collection fails to see the process as a .NET process and subsequently all events that are supposed to be registered and emitted through user_events never come through. Root cause has been identified and is tracked in ns_pid fails to resolve namespace PID for processes in nested PID namespaces microsoft/one-collect#234

• Requesting CPU or thread time traces results in broken stacks, showing shallow stacks instead of the full expected stacks. This is tracked in Several .NET stacks end up in BROKEN state when trace is observed microsoft/one-collect#235

We should also document the expected PID to provide and when this might not work as expected.