PLT-5653 Fix Create channel does not show in another device (#5548)

model/websocket_message.go

@@ -14,6 +14,7 @@ const (
 	WEBSOCKET_EVENT_POST_EDITED        = "post_edited"
 	WEBSOCKET_EVENT_POST_DELETED       = "post_deleted"
 	WEBSOCKET_EVENT_CHANNEL_DELETED    = "channel_deleted"
+	WEBSOCKET_EVENT_CHANNEL_CREATED    = "channel_created"
 	WEBSOCKET_EVENT_DIRECT_ADDED       = "direct_added"
 	WEBSOCKET_EVENT_NEW_USER           = "new_user"
 	WEBSOCKET_EVENT_LEAVE_TEAM         = "leave_team"