MM-8607 Add ability to turn off non-critical services when under load (#13212)

* MM-8607: add ability to turn off non-critical services under load

* server busy invalid param unit tests

* MM-8607: rename server busy endpoints

* MM-8607: handle case where App not initialized

* MM-8607: additional unit test cases per feedback.

* MM-8607: use decorator to check isbusy when adding endpoint route

* MM-8607: rename endpoints, use struct for json

* Update api4/system.go

Fix misspelled log output

Co-Authored-By: Saturnino Abril <saturnino.abril@gmail.com>

* MM-8607: fix i18n order; max seconds for server busy expiry

app/status.go

@@ -228,6 +228,10 @@ func (a *App) SetStatusOnline(userId string, manual bool) {
 }
 
 func (a *App) BroadcastStatus(status *model.Status) {
+	if a.Srv.Busy.IsBusy() {
+		// this is considered a non-critical service and will be disabled when server busy.
+		return
+	}
 	event := model.NewWebSocketEvent(model.WEBSOCKET_EVENT_STATUS_CHANGE, "", "", status.UserId, nil)
 	event.Add("status", status.Status)
 	event.Add("user_id", status.UserId)