MM-53924 - Implement NotificationWillBePushed plugin hook (#24263)

* add NotificationWillBePushed hook

* mocks

* use a struct for hook parameters; simplify number of parameters sent across RPC

* missing wg.Wait

* change to a bool return value

server/public/plugin/hooks_timer_layer_generated.go

@@ -218,3 +218,10 @@ func (hooks *hooksTimerLayer) ConfigurationWillBeSaved(newCfg *model.Config) (*m
 	hooks.recordTime(startTime, "ConfigurationWillBeSaved", _returnsB == nil)
 	return _returnsA, _returnsB
 }
+
+func (hooks *hooksTimerLayer) NotificationWillBePushed(pushNotification *model.PluginPushNotification) (cancel bool) {
+	startTime := timePkg.Now()
+	_returnsA := hooks.hooksImpl.NotificationWillBePushed(pushNotification)
+	hooks.recordTime(startTime, "NotificationWillBePushed", true)
+	return _returnsA
+}