Show an empty state when Protected Environment has no approval rules

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What does this MR do and why?

Show an empty state when Protected Environment has no approval rules

Closes: #393402 (closed)

EE: true

Changelog: changed

Screenshots or screen recordings

Before	After
	after.mov

How to set up and validate locally

1. Run GDK.
2. Create a project with an environment and deployments.
3. Navigate to <project> > Settings > CI/CD > expand a Protected environments.
4. Delete all/Add approval rules (please see the attached video).