Fix StackOverflowError by deeply nested server-timestamps.

[sk-takahiro-kurebayashi]

Summary

This PR fixes app crash by StackOverflowError while saving the document overlay cache into SQLite database inside of Firestore library.

See: #4702

Notes

This PR cannot fix StackOverflowError raised while loading the document overlay cache from SQLite database.
To avoid this crash, we can clear persistent storage by FirebaseFirestore#clearPersistence when right after the app launch.

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[sk-takahiro-kurebayashi]

Hi @ehsannas, let me know how to resolve pr-message check failure. Which feature-branch should I change base-branch to?

[ehsannas]

@sk-takahiro-kurebayashi Thanks for your contribution! 🎉

[ehsannas]

Looks like I need to roll back this change as there were a few integration test failures that were skipped by the CI in this PR.

[ehsannas]

I'll look into the failures and fix them as needed.

[ehsannas]

For now, rolling this PR back via #4761