- Fixes a translation keystring misuse where the string 'open
milestones' is used in place of 'closed milestones'.
- De-duplicates the use of 'open milesones' and 'closed milestones'
keystrings on the sidebar of an issue, reusing the ones on the issues
filter and action bars.
- Closes#32667
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Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>