fix: apply sync node listeners only after auth handler has been attached

[nsrCodes]

Firebase sdk handles all steps synchronously.
Hence, since the sync node listeners get applied before the authHandler callback is applied (effectively a race condition), the rdb interractions inside the authHandler take slightly longer time.

This time increases with increase in the size of the rule payload being fetched from the DB.

These changes add a global state about if the authHandler has been applied. Sync node listeners are attached only after they have been applied.

Although this state is redundant to the already present initializations.auth state, but wanted to keep this separate.

[typo-app]

Typo Code Review 📊

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