Refactor protected environments forms to use ajax

What does this MR do and why?

The create and edit apps for protected environments have been merged together to allow users to create protected environments without needing to refresh the page. Upon a successful create, the edit app is directed to reload the protected environments, fetching the newly created one.

Changelog: changed

Screenshots or screen recordings

Screen_Recording_2023-07-10_at_12.23.44_PM

How to set up and validate locally

1. Install a GitLab premium license
2. Navigate to a projects Settings > CI/CD
3. Expand the Protected Environments section
4. Note no reload is required.

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.

For #375781 (closed)