[Auth-UI][v10.0.0-beta04] Phone auth error dialog ignores AuthUIStringProvider — messages always come back in English

Steps to reproduce:

1. Host PhoneAuthScreen and provide a locale-aware provider via both LocalAuthUIStringProvider and LocalTopLevelDialogController, exactly as documented in the Localization README:
   DefaultAuthUIStringProvider(context, Locale.JAPAN)
2. On the enter-phone-number step, enter a malformed number and tap the send/next button.
3. Observe the ErrorRecoveryDialog shown by dialogController.CurrentDialog()

• error.message over resources for InvalidCredentialsException, UnknownException, PhoneVerificationCooldownException, EmailAlreadyInUseException and AccountLinkingRequiredException
  it builds DefaultAuthUIStringProvider(context) with no locale, so it uses the device locale

• values-zh-rTW ships fui_error_dialog_title = "Authentication Error" and fui_error_retry_action = "Try again" untranslated, while fui_email_link_dismiss_button = 「關閉」 is translated. On a zh-TW device the dialog is mixed-language even when the provider works correctly. values-ja and values-ko have all three.