fix(auth): build auth exceptions with the configured string provider

[demolaf]

Auth error messages were built at throw time from a string provider that was never the one the host configured. Every call site in the provider extensions either passed a bare Context, which resolves against the device locale, or passed nothing and fell through to the raw Firebase SDK string, which is what #2506 hit on the phone path. The correct provider was already in scope at all 21 sites as config.stringProvider.

Routing it through made the top-level dialog controller churn on every recomposition for hosts that build their configuration inline, losing dialogs that had just been shown, so TopLevelDialogController no longer holds a provider and reads LocalAuthUIStringProvider at render time. Its previous constructor and factory are kept as deprecated overloads.

Added routing tests for the converted sites and a dialog-lifetime regression test, each verified to fail on the old code.

[gemini-code-assist]

Code Review

This pull request refactors error message resolution to consistently honor the host's configured AuthUIStringProvider and locale. It updates TopLevelDialogController to resolve strings from LocalAuthUIStringProvider at render time, deprecates explicit provider arguments, and adds comprehensive unit tests for localized error routing across all auth providers. A critical stale lambda capture bug was identified in rememberTopLevelDialogController where the unkeyed remember block caches the initial authState lambda, preventing the controller from receiving updated state in production. It is recommended to use rememberUpdatedState to resolve this issue.