Add warning when Token Access disabled

What does this MR do and why?

Related to #340494 (comment 1097280367)

• Add warning message when Access Token is disabled
• Add space between Add an existing project to the scope form and Projects that can be accessed table

Screenshots or screen recordings

Access token ON state

Before

After

Access token OFF state

Before

After

How to set up and validate locally

1. On the top bar, select Menu > Projects and find your project.
2. On the left sidebar, select Settings > CI/CD.
3. Expand Token Access.
4. Toggle Limit CI_JOB_TOKEN access to disabled.

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 #340494 (closed)