Order hierarchy by notation

[UnniKohonen]

Reasons for creating this PR

Hierarchy is currently only ordered by labels. It should be possible to order it by notation codes as well

Link to relevant issue(s), if any

• Part of Epic: Implement hierarchical view in sidebar using Vue #1521

Description of the changes in this PR

Sort concepts based on notation codes using both lexical and natural sorting.

Addresses requirement 6d in #1521

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)

[osma]

Seems to work very well on the example vocabularies I tested (YKL, YSO-aika, okm-tieteenala). However, we don't really have a recent use case for numeric sorting of notations (the PTVL classification that required this was removed from Finto some time ago) so I couldn't test that with a real example. Anyway, I suppose it's good enough given that we don't even need it at the moment :)

I'd like to see Cypress tests that verify that the order in the hierarchy follows the notations, could you add some? I know that we're currently lacking Cypress tests for a lot of sidebar functionality, so adding tests could also be done as a separate effort if you prefer.

I made a suggestion to rename the compareStrs function to compareConcepts.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[osma]

LGTM!