HTTP: Clear callbacks on HTTP requests during shutdown to prevent crashes

[seer-by-sentry]

Fixes CLIENT-KW. The issue was that: HTTP request callbacks execute during shutdown after captured objects, like WebSocket, have been destroyed.

• Added ClearCallbacks method to HTTPRequest to nullify completion and progress callbacks.
• Called ClearCallbacks on all in-flight HTTP requests during HTTPManager shutdown to prevent accessing destroyed objects.

This fix was generated by Seer in Sentry, triggered automatically. 👁️ Run ID: 2086980

Not quite right? Click here to continue debugging with Seer.