fix: Refactor and fix AppLayout and side navigation panel state and behaviour

[rubencarvalho]

Description

Re-adding #1434. It was reverted (#1485) to unblock our pipelines. We had a problem in our integration tests setup. Now, the fix for the tests has been deployed (CR-99922192), meaning this PR can finally be merged!

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

Patch coverage: 100.00% and project coverage change: +0.01% 🎉

Comparison is base (334a015) 93.80% compared to head (cb4b7d4) 93.82%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1490      +/-   ##
==========================================
+ Coverage   93.80%   93.82%   +0.01%     
==========================================
  Files         639      640       +1     
  Lines       17245    17244       -1     
  Branches     5675     5671       -4     
==========================================
+ Hits        16177    16179       +2     
+ Misses        995      992       -3     
  Partials       73       73              

Files Changed	Coverage Δ
...c/expandable-section/expandable-section-header.tsx	100.00% <ø> (ø)
src/side-navigation/internal.tsx	100.00% <ø> (ø)
src/app-layout/index.tsx	92.83% <100.00%> (+0.05%)	⬆️
src/app-layout/visual-refresh/context.tsx	89.51% <100.00%> (+0.14%)	⬆️

... and 5 files with indirect coverage changes

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