Link to environment detail page for deployment approvals

What does this MR do and why?

Implements #418119 (closed).

The CTA on the "approval required" page was linking to the environments overview page, which could lead to confusion. This MR links the CTA button to the specific environment instead, resulting in a more streamlined process.

Screenshots or screen recordings

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Before	After

How to set up and validate locally

1. Create new project
2. Add this CI config:

   production:
     script:
       - 'echo "Deploying to ${CI_ENVIRONMENT_NAME}"'
     environment:
       name: ${CI_JOB_NAME}

3. Run pipeline
4. Go to CI/CD settings, set production environment to protected
5. Run pipeline again
6. Observe changed text on approval required page

MR acceptance checklist

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