Follow #32460
Now the code could be much clearer than before and easier to maintain. A
lot of legacy code is removed.
Manually tested.
This PR is large enough, that fine tunes could be deferred to the future if
there is no bug found or design problem.
Screenshots:
<details>
![image](https://github.com/user-attachments/assets/35f4ab7b-1bc0-4bad-a73c-a4569328303c)
</details>
#26996
Added default sorting for milestones by name.
Additional, name for sorting closestduedate and furthestduedate was
broken, so I fixed it.
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Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>