Remove the search language cookie

[joelit]

Reasons for creating this PR

There was unnecessary state management between URL parameters and language cookies for search language. This PR aims to clarify the situation while fixing a minor bug. Supersedes the previous PR #1693 .

Link to relevant issue(s), if any

• Closes Content language setting is not working consistently in Skosmos 3 #1692

Description of the changes in this PR

• Remove the SKOSMOS_SEARCH_LANG cookie alltogether

Known problems or uncertainties in this PR

None.

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)

[sonarcloud]

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 SonarQube Cloud