Direction Kick-off: Use Premium bullet for issues and epics labeled as Starter/Premium

Why is this change being made?

The direction kickoff page fetches the issues/epics for a specific version and then generates the list representations. This is done in generators/direction.rb, specifically issue_bullet() and epic_bullet(). These functions are not used anywhere else but the Direction page.

Users see the direction kick-off page as roadmap for the next releases and years. Seeing the Starter bullet next to issue could be misleading, as it is nowhere else on the website.

gitlab-org/gitlab#293864 (comment 509529531) explains a necessity to keep the Starter label for engineering on existing features.

To solve this confusion on the website only, I'd like to propose overriding the rendered text from issue labels until Starter is fully faded out.

Please discuss, I am not 100% confident that this is the correct solution.

Author Checklist

• Provided a concise title for the MR
• Added a description to this MR explaining the reasons for the proposed change, per say-why-not-just-what
• Assign this change to the correct DRI
  • If the DRI for the page/s being updated isn’t immediately clear, then assign it to one of the people listed in the "Maintained by" section in on the page being edited.
  • If your manager does not have merge rights, please ask someone to merge it AFTER it has been approved by your manager in #mr-buddies.
  • If the changes relate to any part of the project other than updates to content and/or data files please make sure to ping @gl-static-site-editor in a comment for a review and merge. For example changes to .gitlab-ci.yml, JavaScript/CSS/Ruby code or the layout files. (this requirement has been removed pending identification of a new DRI for the handbook)