chore: Updates drawers tests

[katiegeorge]

Description

As part of moving drawers from beta to public, we made the decision to change the name of findDrawersSlider to findActiveDrawerResizeHandle. We also decided findDrawersDesktopTriggersContainer and findDrawersMobileTriggersContainer were unnecessary and added bloat, so I removed the instances of those and refactored the tests that used them.

Related links, issue #, if available: n/a

How has this been tested?

Review checklist

The following items are to be evaluated by the author(s) and the reviewer(s).

Correctness

• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
• Changes do not include unsupported browser features, see CONTRIBUTING.md.
• Changes were manually tested for accessibility, see accessibility guidelines.

Security

• If the code handles URLs: all URLs are validated through the checkSafeUrl function.

Testing

• Changes are covered with new/existing unit tests?
• Changes are covered with new/existing integration tests?

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[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (2a586a4) 94.05% compared to head (3ddaf51) 94.04%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1588      +/-   ##
==========================================
- Coverage   94.05%   94.04%   -0.02%     
==========================================
  Files         649      649              
  Lines       17584    17579       -5     
  Branches     5781     5780       -1     
==========================================
- Hits        16539    16532       -7     
- Misses        976      978       +2     
  Partials       69       69              

Files	Coverage Δ
src/app-layout/drawer/index.tsx	98.57% <100.00%> (-0.03%)	⬇️
src/app-layout/mobile-toolbar/index.tsx	94.28% <100.00%> (ø)
src/app-layout/visual-refresh/drawers.tsx	91.76% <ø> (ø)
src/test-utils/dom/app-layout/index.ts	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes

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[just-boris]

Rebased because #1597 added more tests that now need rename