fix(firestore, android): catch RejectedExecutionException in sendOnSnapshotEvent

[christian-apollo]

Summary

• Fixes [🐛] Firestore Android: RejectedExecutionException crash in sendOnSnapshotEvent during module invalidation #8973

• Wrap Tasks.call() in sendOnSnapshotEvent with a try-catch for RejectedExecutionException in both ReactNativeFirebaseFirestoreCollectionModule and ReactNativeFirebaseFirestoreDocumentModule

• Prevents a fatal crash when a Firestore snapshot callback (already enqueued on the main looper via AsyncEventListener) fires after module invalidation has terminated the executor

Context

The existing invalidate() correctly removes listeners before calling super.invalidate(). But AsyncEventListener dispatches via Handler.post() — if a snapshot event is already in the Handler queue before invalidation starts, it will still run sendOnSnapshotEvent after the executor is shut down. This is a standard executor-shutdown race that reordering alone cannot prevent.

Dropping the event is safe because the module is tearing down and no JS listener remains to consume it.

Test plan

• Verified the crash no longer reproduces by running with active Firestore collection listeners and forcing rapid module invalidation cycles
• Confirmed normal snapshot delivery is unaffected — the catch only activates when the executor is already terminated

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Note

Low Risk
Low risk: adds defensive RejectedExecutionException handling around async executor usage during module teardown to prevent crashes; behavior only changes in teardown/race scenarios.

Overview
Prevents Android crashes when Firestore/Realtime Database callbacks arrive after module invalidation has shut down the executor.

Wraps several Tasks.call(...) usages in Firestore collection/document snapshot delivery, Firestore transaction getDocument, and Realtime Database once/event dispatch with try/catch (RejectedExecutionException), rejecting the pending promise (for get/once) or safely dropping late snapshot/events during teardown. Also reorders DatabaseQueryModule.invalidate() to clean up listeners before calling super.invalidate().

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[gemini-code-assist]

Code Review

This pull request introduces error handling for RejectedExecutionException in the sendOnSnapshotEvent methods within both ReactNativeFirebaseFirestoreCollectionModule and ReactNativeFirebaseFirestoreDocumentModule. By wrapping the task execution in a try-catch block, the code now gracefully handles snapshots that arrive after the module's executor has been shut down during teardown. I have no feedback to provide as there were no review comments to evaluate.

[mikehardy]

Thanks for your patience! I like this PR so much (and the genre of issue it exposes) that I did a quick scan over the whole codebase for similar patterns and turned up some extra instances in firestore and rtdb packages

I'm going to add those as follow-on commits in your branch on this PR so the single PR contains one conclusive fix for the genre of issue you discovered, and shepherd it to merge