PLT-3942 Add real-time updates for center channel profile picture popover (#3871)

* PLT-3942 Add real-time updates for center channel profile picture pop-over

* Send user data with the websocket event to prevent further requests

* Add helper for profile sanitation

model/websocket_message.go

@@ -19,6 +19,7 @@ const (
 	WEBSOCKET_EVENT_NEW_USER           = "new_user"
 	WEBSOCKET_EVENT_LEAVE_TEAM         = "leave_team"
 	WEBSOCKET_EVENT_USER_ADDED         = "user_added"
+	WEBSOCKET_EVENT_USER_UPDATED       = "user_updated"
 	WEBSOCKET_EVENT_USER_REMOVED       = "user_removed"
 	WEBSOCKET_EVENT_PREFERENCE_CHANGED = "preference_changed"
 	WEBSOCKET_EVENT_EPHEMERAL_MESSAGE  = "ephemeral_message"