feat(profiling): stop profiler on context end

[Litarnus]

The profiler will now also be stopped once a RuntimeContext ends to prevent any leaks. In runtimes such as FrankenPHP, a non properly finished transaction might keep a span alive and would never stop the profiler.

This only applies to trace profiling because only that will populate the root spans, manual tracing is unaffected

[cursor]

Cursor Bugbot has reviewed your changes and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

^{Reviewed by Cursor Bugbot for commit fd646f3. Configure here.}