Milestone burndown chart consistency fixes
What does this MR do and why?
Burndown charts on Milestones and Iterations have slightly different styling for reasons that no one currently remembers. This seems to be related to an ancient (5+ year old) refactor of charts in general and remaining styles that were necessary before that refactor and were not removed at the time.
In order to make burndown/up charts consistent across Iterations and Milestones, this MR removes unnecessary legacy styles that affected burndown charts on milestone pages and adjusts styling of toggle buttons used to select legacy vs fixed burndown charts.
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Screenshots or screen recordings
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How to set up and validate locally
- Check out this branch
- Navigate to a Milestone (for example, http://gdk.test:3000/gitlab-org/gitlab-test/-/milestones/3#tab-issues)
- If necessary, add a start and end date to the milestone in order to get burndown/burnup charts displayed
- In another tab or window, open an iteration (for example, http://gdk.test:3000/groups/gitlab-org/-/cadences/1479/iterations/9350)
- You should see that the Iteration version of the Burndown/up charts and the Milestone version have the same styling (though note that the iteration will have an extra "Completed"/"Incomplete"/"Unstarted" element between the "Display by" line and the charts, and the Milestone version will have an extra toggle between legacy and fixed burndown charts)
Related to #424397 (closed)