Add help popover for users with no access to projects

What does this MR do and why?

Add help popover for users with no access to projects

This change to the project runner details page adds a popover to signal to users that they may not be able to see some projects the the runner was assigned to.

Changelog: changed

References

• An alternative to !188753 (merged)
• Part of #33803 (closed)

Screenshots or screen recordings

Before	After

How to set up and validate locally

Given a runner that is assigned to a few projects.

1. With the FF vue_project_runners_settings enabled
2. Log in as a maintainer of a project. (Don't use an admin, they already have access to all projects)
3. Visit one of the projects and go to CI/CD settings -> Runners
4. View the details of your project runner, verify the count and list of projects is correct.

Note: vue_project_runners_settings just make this easier to access, this change is not behind a feature flag.

MR acceptance checklist

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Related to #33803 (closed)