Remove uses of @gitlab/ui scss_to_js

What does this MR do and why?

Remove uses of @gitlab/ui/scss_to_js

This will be deprecated in a future gitlab-ui release. Replace with /dist/tokens/js/tokens.js which has these values.

Screenshots or screen recordings

No visual changes.

How to set up and validate locally

The components using these values were:

• Issues analytics -> Total issues
• Projects -> Learn GitLab -> Circular progress bar

No visual/functional changes expected.

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.