Migrate `form_errors` in _repository_check.html.haml to Pajamas alert

What does this MR do and why?

Migrate form_errors in app/views/admin/application_settings/_repository_check.html.haml to Pajamas::AlertComponent.

Screenshots or screen recordings

Scenario	Screenshot
Before
After

How to set up and validate locally

1. Login as admin in your local GDK.
2. Go to Settings -> Repository from the left menu
3. Expand the Repository maintenance section. (http://localhost:3000/admin/application_settings/repository#js-repository-check-settings)
4. Enter negative values in all the 3 number fields.
5. Click on Save changes.
6. Observe that alert is shown.

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 #364916 (closed)