Optionaloptions: { disableWarnings: boolean }Delegates to the native useEmulator bridge. Accepts the firebase-js-sdk
options.disableWarnings flag for Auth.emulatorConfig parity. On web, that flag
suppresses the emulator DOM warning banner; native iOS/Android SDKs do not surface that banner,
so the value is recorded on auth.emulatorConfig.options only. When options is provided,
disableWarnings is required (matching firebase-js-sdk).
Connects the Auth instance to the Auth emulator.