fix http stream headers

Author: RachitKumar205

backend/internal/controllers/controllers.go

@@ -72,6 +72,11 @@ func TeamChannelEventHandler(rtr *router.Router) http.HandlerFunc {
 		listenerChannel := make(chan protocol.Packet)
 		teamChannel.AddMember(listenerChannel)
 
+		w.Header().Set("Content-Type", "text/event-stream")
+		w.Header().Set("Cache-Control", "no-cache")
+		w.Header().Set("Connection", "keep-alive")
+		w.WriteHeader(http.StatusOK)
+
 		flusher, ok := w.(http.Flusher)
 		if !ok {