Add Cypress tests for partial page load

[osma]

Reasons for creating this PR

This PR adds more Cypress tests for verifying functionality during and after partial page loads.

Link to relevant issue(s), if any

• Closes Cypress tests for partial page load #1598

Description of the changes in this PR

• modify the Cypress tests for the concept page so that the most important tests related to dynamic functionality (title, URI, copy to clipboard, mappings) are run both with full and partial page loads
• change the declaration of the SKOSMOS global object from const SKOSMOS to window.SKOSMOS, and all references to it to window.SKOSMOS (this makes it accessible on the Cypress side)
• add tests to the vocab-home cypress test suite for verifying partial page load functionality when clicking concepts in the sidebar (hierarchy and alphabetical index); also verify that window.SKOSMOS has been properly updated after partial page load

Known problems or uncertainties in this PR

Cypress/Electron appears to have problems getting stuck with cy.visit(url) in case the URL has already been loaded by the tested application using AJAX style requests. The code in the PR avoids this situation by using different example concept pages for the partial page load tests than for the subsequent tests that perform full page loads. See this comment for some details.

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)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 70.58%. Comparing base (223ddd2) to head (a7150b7).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main    #1605   +/-   ##
=========================================
  Coverage     70.58%   70.58%           
  Complexity     1647     1647           
=========================================
  Files            32       32           
  Lines          4321     4321           
=========================================
  Hits           3050     3050           
  Misses         1271     1271           

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[UnniKohonen]

This looks good to me, but I'm wondering if mappings should be checked on vocab home page too.

[sonarcloud]

Quality Gate failed

Failed conditions
35.1% Duplication on New Code (required ≤ 3%)

See analysis details on SonarCloud

[osma]

@UnniKohonen I added tests for mappings as well. All good now?

[UnniKohonen]

LGTM!