feat: DH-19722: Better handling for large numbers of open dashboards

[gzh2003]

For DH-19722. This PR adds a popper for searching and filtering through dashboards. It supports keyboard navigation and includes a global shortcut (Ctrl+Shift+D / Cmd+Shift+D) to toggle the quick filter popper.

Changes:

• Dashboard search: Filter dashboards by typing in the search input
• Global shortcut: Ctrl+Shift+D/Cmd+Shift+D opens the dashboard search popper (only when 2+ dashboards exist)
• Keyboard interactions: arrow keys navigate between dashboard items; enter sets the active dashboard to the currently focused item in the list (if no dashboard in the list is focused it will default to the first dashboard in the search)
• Adds 'endPlaceholder' to SearchInput to display the associated shortcut

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 78 lines in your changes missing coverage. Please review.

Project coverage is 44.59%. Comparing base (e32b68f) to head (4608893).
Report is 16 commits behind head on main.

Files with missing lines	Patch %	Lines
...ckages/components/src/navigation/DashboardList.tsx	0.00%	62 Missing ⚠️
packages/components/src/navigation/NavTabList.tsx	0.00%	13 Missing ⚠️
packages/components/src/SearchInput.tsx	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2481      +/-   ##
==========================================
- Coverage   44.62%   44.59%   -0.04%     
==========================================
  Files         759      763       +4     
  Lines       42548    42692     +144     
  Branches    10693    10734      +41     
==========================================
+ Hits        18988    19038      +50     
- Misses      23549    23643      +94     
  Partials       11       11              

Flag	Coverage Δ
unit	44.59% <0.00%> (-0.04%)	⬇️

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[gzh2003]

I'm not a fan of mousedown on the dashboard list stealing focus from the search input. The list items already have CSS styling for this, so I think retaining focus on the search input keeps things cleaner.

[mofojed]

Yea, I generally try to avoid capturing just a mouse down or a mouse up, as that could potentially cause issues for any other libraries or cause issues with accessibility... seems okay for this case.
In another scenario, eating just an mouseup event could screw up anything that had started listening for mousedown and then expected a mouseup... Capturing down is a little less dangerous though.

[mofojed]

Couple minor things, looks good