Add authContext extension to FDC mutationExecuted event

https://github.com/cloudevents/spec/blob/main/cloudevents/extensions/authcontext.md

PiperOrigin-RevId: 810113088

Author: yoshi-code-bot

proto/google/events/firebase/dataconnect/v1/events.proto

@@ -143,6 +143,9 @@ message MutationExecutedEvent {
   option (google.events.cloud_event_extension_name) = "connector";
   option (google.events.cloud_event_extension_name) = "service";
   option (google.events.cloud_event_extension_name) = "operation";
+  option (google.events.cloud_event_extension_name) = "authtype";
+  option (google.events.cloud_event_extension_name) = "authid";
+  option (google.events.cloud_event_extension_name) = "authclaims";
 
   // The data associated with the event.
   MutationEventData data = 1;