Dynamics popup refinements (lower-priority)

[avvvvve]

Refinements to #24125
Note: More important refinements are noted in #26018. Work on those first!

See issues 4, 5, 7, 8, and 9 from my comment here (pasted below, but there's some discussion at the link)

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4. If I click on the dynamic again after selecting it, the popup should be dismissed. Clicking it again should open it again. See the sound flag popup for an example of how this is already implemented. Example of why you'd want this: the popup is dismissed when scrolled (expected behavior), but you have to deselect and reselect the dynamic if you want to see the popup again.

sound_flag_dismiss.mov

5. When I click a dynamic in the score that isn't on the first page of the popup, it should call up the page it's on.
   Current behavior (the first page shows up every time):
   
   Expected behavior:
   

6. When clicking the left arrow to cycle through pages, the rightmost dynamic in the popup has the darker hover state, but it shouldn't

dyn_pop_left_hover.mov

(Video for both 8 and 9 below)

8. If a dynamic is selected that is immediately followed by a crescendo/decrescendo that is snapped to the dynamic, using the cresc/dec buttons in the popup currently add additional hairpin objects. Perhaps they should replace the existing one when clicked (or do nothing if a crescendo exists and a crescendo is clicked).

9. The popup shifts around a little bit when different dynamics are selected. It would be nice if the popup remained in the same place while clicking different dynamics. The position could then update the next time the popup is opened.

dyn_pop_cresc_jiggle.mov