Merge branch '216326-fix-form-for-alerts-slack-setting' into 'master'

Add alert_events param to permitted

Closes #216326

See merge request gitlab-org/gitlab!34133

app/controllers/concerns/service_params.rb

@@ -6,6 +6,7 @@ module ServiceParams
   ALLOWED_PARAMS_CE = [
     :active,
     :add_pusher,
+    :alert_events,
     :api_key,
     :api_url,
     :api_version,