Remove old Alert components on integration pages

Background

It has been 1 year since we added Alert messages to the the Admin area and the project integration screen. The purpose of both messages was to inform users that some items from the screens had been moved.

Now with milestone %14.0 approaching, it seems like a good time to do some cleanup work and remove these Alerts.

Related issues:

• Admin Area: Add Instance-Level Integration Settings UI
• Add message to Integrations page about Webhooks changes

Admin Area: Add Instance-Level Integration Settings UI	Add message to Integrations page about Webhooks changes

Proposal

• Remove Alert banner from /admin/application_settings/integrations
• Remove Alert banner from /<project>/-/settings/integrations