fix: allow overflow scroll for widget list and dashboard overlow list.

[dsmmcken]

Dashboard list overflows, but would not be selectable, made selectable and extend over to overflow. Panels list would wrap text (which worked before it was a spectrum list, which now needs same height items), now overflow scroll on x and y.

Before:

After:

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 44.36%. Comparing base (4ee9308) to head (7b9b7ee).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2558      +/-   ##
==========================================
+ Coverage   44.08%   44.36%   +0.28%     
==========================================
  Files         764      764              
  Lines       43078    43104      +26     
  Branches    11066    10895     -171     
==========================================
+ Hits        18990    19125     +135     
+ Misses      24041    23963      -78     
+ Partials       47       16      -31     

Flag	Coverage Δ
unit	44.36% <ø> (+0.28%)	⬆️

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[mofojed]

With only two dashboards, it looks strange. Tested with:

from deephaven import ui

fjdsiopajfiodjsaoifjdsoiafjdiosajfoidsjafoidjsaoifjdsoiajfds = ui.dashboard(ui.panel("Hello"))
fjdsiopajfiodjsaoifjdsoiafjdiosajfoidsjafoidjsaoifjdsoiajfds2 = ui.dashboard(ui.panel("Hello"))

The right arrow seems to overlap the last characters of the last dashboard in the list, and pressing on the right arrow doesn't seem to work...:

Looks good when the lists are full though

[dsmmcken]

NavTabList isn't re-used in enterprise -- it's actually quite a few bugs behind what looks like we refactored here. Probably worth de-duplicating to pick up the various bug fixes.

Fixed case when left edge of tab is still on screen at the right, but the right edge of a tab is offscreen to the right, and it not scrolling in.

Fixed list for less than full amount of items.