Fix#27466
The problem is that any item in the menu could be hidden, pure CSS won't
work, and dropdown's builtin "hideDividers" doesn't work with our "scope
dividers". The newly introduced "archived" label makes the dividers
regression more.
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:
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![image](https://github.com/user-attachments/assets/35f4ab7b-1bc0-4bad-a73c-a4569328303c)
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