Show play button on environment detail page to deployment-only users

What does this MR do and why?

Shows the play button on the environment detail page to deployment-only users.

Related to #341182 (closed)

Screenshots or screen recordings

Screenshots were taken while impersonating a deployment-only user. See !101400 (merged) for setup.

Before

After

How to set up and validate locally

1. Set up Deployment-only access to a protected environment.
2. Create a deployment (if none exist already) with a manual job in the pipeline.
3. As the user with deployment-only access, navigate to the environment details page.
4. Verify that the play buttons are visible and show the manual job.

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.