Remove links to Metrics in Environments

What does this MR do and why?

Describe in detail what your merge request does and why.

Remove links to Metrics in [project] > Deployments >Environments and [project] > Deployments >Environments > [environment]

I've also added a small accessibility improvement - a missing aria-label to Rollback environment button on single environment view.

Screenshots or screen recordings

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There is no visible change, these sections are already hidden behind the feature flag.

How to set up and validate locally

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

There is no visible change, these sections are already hidden behind the feature flag.

• Make sure the pipeline passes
• On your GDK visit http://127.0.0.1:3000/flightjs/Flight/-/environments & http://127.0.0.1:3000/flightjs/Flight/-/environments/6 and make sure there are no errors in the console

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 #393929 (closed)