feat(api): return eventify_id in StatusView response

Adds `eventify_id` to the `/api/user/status/` endpoint so that
`initProfileTickets` can fetch the EVT-XXXXXXXX badge for users
whose localStorage session pre-dates the eventify_id login field.

mobile_api/views/user.py

@@ -122,7 +122,8 @@ class StatusView(View):
             return JsonResponse({
                 "status": "logged_in",
                 "username": user.username,
-                "email": user.email
+                "email": user.email,
+                "eventify_id": user.eventify_id or '',
             })
 
         except Exception as e: