Fix switching between sidebar tabs using the keybaord

[UnniKohonen]

Reasons for creating this PR

Switching between sidebar tabs using the arrow keys does not currently load the contents of the tabs. This PR fixes the way tab contents are loaded. Contents should now be loaded when tabs are clicked and when switching between them with arrow keys.

Description of the changes in this PR

• Listen to bootstrap's tab shown event instead of click events in sidebar tabs to load tab content
• Add cypress test

Known problems or uncertainties in this PR

Checklist

• phpUnit tests pass locally with my changes
• I have added tests that show that the new code works, or tests are not relevant for this PR (e.g. only HTML/CSS changes)
• The PR doesn't reduce accessibility of the front-end code (e.g. tab focus, scaling to different resolutions, use of .sr-only class, color contrast)
• The PR doesn't introduce unintended code changes (e.g. empty lines or useless reindentation)

[qltysh]

2 new issues

Tool	Category	Rule	Count
qlty	Structure	Function with many returns (count = 12): startGroupsApp	2

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.42%. Comparing base (527659b) to head (c83eb87).

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #2029   +/-   ##
=========================================
  Coverage     70.42%   70.42%           
  Complexity     1703     1703           
=========================================
  Files            34       34           
  Lines          4436     4436           
=========================================
  Hits           3124     3124           
  Misses         1312     1312           

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[osma]

Fix looks sane and works perfectly (tested under Firefox and Chromium).