add export for totpGenerator for react native bundle

Author: bhparijat

packages/auth/index.rn.ts

@@ -47,6 +47,7 @@ export {
 
 // MFA
 export { PhoneMultiFactorGenerator } from './src/platform_browser/mfa/assertions/phone';
+export {TotpMultiFactorGenerator} from './src/mfa/assertions/totp';
 
 export { getReactNativePersistence } from './src/platform_react_native/persistence/react_native';