fix(auth): fix "Already resumed" crash in phone auth SMS auto-verification

[demolaf]

Closes #2446

• DefaultVerifier.verifyPhoneNumber resumed the same suspendCoroutine from all three Firebase phone-auth callbacks; a second callback (e.g. onCodeSent then SMS auto-retrieval's onVerificationCompleted) threw IllegalStateException: Already resumed on the main thread, uncatchable, fatal.
• Guarded with a single AtomicBoolean latch shared across all three callbacks — first callback wins, later ones are dropped and logged instead of throwing. Switched to suspendCancellableCoroutine.

[gemini-code-assist]

Code Review

This pull request expands the demo application to showcase Firebase Database, Firestore, and Storage modules alongside the existing Auth module, introducing new demo activities and paging adapters. It also refactors the Auth module's state management by introducing AuthState.Aborted to distinguish full-flow cancellations from operation-level cancellations (AuthState.Cancelled), and adds an isNotification property to prevent transient states from leaking across screen recreations. Additionally, it resolves a continuation resumption crash in phone verification, fixes a dialog de-duplication bug in TopLevelDialogController, and enhances security by enabling touch filtering when obscured. The reviewer suggested broadening the documentation for the identifier parameter in AuthMethodPicker to include phone numbers as well as email addresses.

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auth/src/main/java/com/firebase/ui/auth/ui/method_picker/AuthMethodPicker.kt (227)

The documentation for the identifier parameter has become too restrictive. The SignInPreferenceManager can store either an email address or a phone number. This comment should be updated to reflect that to avoid confusion for developers using this component.

 * @param identifier The user identifier (email or phone number)