Migrate `form_errors` in new application to Pajamas alert

What does this MR do and why?

Migrate form_errors in app/views/admin/applications/_form.html.haml to Pajamas::AlertComponent.

Screenshots or screen recordings

Scenario	Screenshot
Before
After

How to set up and validate locally

1. In your local GDK login using an admin user.
2. In the admin section go to Applications (http://localhost:3000/admin/applications).
3. Click New application.
4. Enter any Name and click on Save application (Do not add fill any other field).
5. Observe that alert is shown.

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #364963 (closed)