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/plugintest/hooks.go

@@ -193,6 +193,20 @@ func (_m *Hooks) MessageWillBeUpdated(c *plugin.Context, newPost *model.Post, ol
 	return r0, r1
 }
 
+// NotificationWillBePushed provides a mock function with given fields: pushNotification
+func (_m *Hooks) NotificationWillBePushed(pushNotification *model.PluginPushNotification) bool {
+	ret := _m.Called(pushNotification)
+
+	var r0 bool
+	if rf, ok := ret.Get(0).(func(*model.PluginPushNotification) bool); ok {
+		r0 = rf(pushNotification)
+	} else {
+		r0 = ret.Get(0).(bool)
+	}
+
+	return r0
+}
+
 // OnActivate provides a mock function with given fields:
 func (_m *Hooks) OnActivate() error {
 	ret := _m.Called()