[release/6.0-rc1] [debugger] Avoid calling debugger_agent_single_step_from_context when thread is not attached yet#58480

mmitche merged 2 commits intorelease/6.0-rc1dotnet/runtime:release/6.0-rc1from

backport/pr-58467-to-release/6.0-rc1dotnet/runtime:backport/pr-58467-to-release/6.0-rc1Copy head branch name to clipboard