Migrate CSS rules to utility classes in app/assets/stylesheets/page_bundles/jira_connect_users.scss

Migrate CSS rules to utility classes in app/assets/stylesheets/page_bundles/jira_connect_users.scss

• Use our utility classes reference to find equivalent replacements or combinations: https://unpkg.com/browse/@gitlab/ui@latest/src/scss/utilities.scss
• Delete unused or dead code
• Perform a visual regression test on the page your migrating CSS for.

In your Merge Request description, please include the number of CSS lines you deleted (this is to track the progress of our OKR):

Number of CSS lines deleted: