fix: call e2eRotate on existing conversations [WPB-24528]

[e-maad]

WPB-24528 [Web] User not able to send messages after e2ei was enbaled while user is logged in

Summary

When we enable e2eI for existing MLS client, all the conversations must me called with e2eiRotate.

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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Screenshots or demo (if the user interface changed)

Notes for reviewers

• Trade-offs:
• Follow-ups (linked issues):
• Linked PRs (e.g. web-packages):

[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 SonarQube Cloud

[github-actions]

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🧪 Playwright Test Summary

• ✅ Passed: 14
• ❌ Failed: 0
• ⏭ Skipped: 0
• 🔁 Flaky: 0
• 📊 Total: 14
• ⏱ Total Runtime: 521.8s (~ 8 min 42 sec)