Apply relevant scope data to user feedback

[limbonaut]

Currently user feedback does not carry scope data, but it should. Expected: environment, tags, release etc.
Check feedback spec for more details.

SDKs MUST apply scope data to the feedback event, including tags, user, trace, and contexts.

Currently, user feedback is sent without trace, so it's not connected to the same trace as errors.

[linear-code]

NATIVE-202

[sentry-pierre]

Confirmed in the source. prepare_user_feedback builds a bare event and never calls sentry__scope_apply_to_event, so release, environment, tags, user, and trace context are all skipped. The fix should be a straightforward scope merge before the envelope is finalized.