test: add mention regression tests [WPB-19960]

[markbrockhoff]

WPB-19960 [Web/QA] Write the Mention regression tests in Playwright

Pull Request

Summary

• Implement regression tests for mentioning other users in messages
• Fix aria label of decline button within call cell
• Group conversation list item locators e.g. for unread or mention status
• Fix a11y within UserList to correctly label the group admin and member lists
• Create setup for adding guest users to a group conversation

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Security Checklist (required)

• External inputs are validated & sanitized on client and/or server where applicable.
• API responses are validated; unexpected shapes are handled safely (fallbacks or errors).
• No unsafe HTML is rendered; if unavoidable, sanitization is applied and documented where it happens.
• Injection risks (XSS/SQL/command) are prevented via safe APIs and/or escaping.

Accessibility (required)

• I have read and this PR upholds our Accessibility Best Practices.

Standards Acknowledgement (required)

• I have read and this PR upholds our Coding Standards and Tech Radar Choices.

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Notes for reviewers

• This PR is on the bigger side, but I made sure all commits inside it are atomic. So instead of looking at everything at once, you may step through the individual commits one after an other during review to reduce the cognitive overhead ;)

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 45.59%. Comparing base (48d14dc) to head (d3deea0).
⚠️ Report is 16 commits behind head on dev.

Additional details and impacted files

@@           Coverage Diff           @@
##              dev   #20498   +/-   ##
=======================================
  Coverage   45.58%   45.59%           
=======================================
  Files        1641     1641           
  Lines       40496    40496           
  Branches     8354     8352    -2     
=======================================
+ Hits        18461    18463    +2     
  Misses      20097    20097           
+ Partials     1938     1936    -2     

Flag	Coverage Δ
app_webapp	43.79% <100.00%> (+<0.01%)	⬆️
lib_api_client	50.17% <ø> (ø)
lib_core	59.34% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
...webapp/src/script/components/UserList/UserList.tsx	71.91% <100.00%> (+0.64%)	⬆️
...ipt/components/calling/CallingCell/CallingCell.tsx	46.49% <ø> (ø)
...ng/CallingCell/CallingControls/CallingControls.tsx	33.33% <ø> (+1.90%)	⬆️

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[github-actions]

🔗 Download Full Report Artifact

🧪 Playwright Test Summary

• ✅ Passed: 225
• ❌ Failed: 0
• ⏭ Skipped: 13
• 🔁 Flaky: 2
• 📊 Total: 240
• ⏱ Total Runtime: 400.6s (~ 6 min 41 sec)

specs/Authentication/authentication.spec.ts (❌ 0 failed, ⚠️ 1 flaky)

• ⚠️ Authentication > Make sure user does not see data of user of previous sessions on same browser (tags: TC-1311, regression)

specs/ParticipantProfile/participantProfile.spec.ts (❌ 0 failed, ⚠️ 1 flaky)

• ⚠️ Participant Profile > I should not to see Remove from group as a member on participants profile (tags: TC-1488, regression)

[sonarqubecloud]

Quality Gate failed

Failed conditions
10.4% Duplication on New Code (required ≤ 5%)

See analysis details on SonarQube Cloud