Integrate email notifications into signup and login (#38)

frontend/packages/sxchnge_auth/lib/src/services/instrumented.dart

@@ -56,6 +56,7 @@ class InstrumentedAuthServices
     } catch (error) {
       final failure = switch (error) {
         AuthException(code: final code) => switch (code) {
+          AuthError.accountNotVerified => JourneyFailure.invalid,
           AuthError.invalidCredentials => JourneyFailure.invalidCredentials,
           AuthError.emailInUse => JourneyFailure.emailInUse,
           AuthError.unavailable => JourneyFailure.unavailable,