fix: mls decrypted messages not shown in NSE - WPB-23426

[netbe]

WPB-23426 [iOS] mls decrypted messages not shown in NSE

Issue

Generates a notification for all decrypted messages returned from a mls message add event, not only the first one.

Testing

• update unit tests

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Checklist

• Title contains a reference JIRA issue number like [WPB-XXX].
• Description is filled and free of optional paragraphs.
• Adds/updates automated tests.

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UI accessibility checklist

If your PR includes UI changes, please utilize this checklist:

• Make sure you use the API for UI elements that support large fonts.
• All colors are taken from WireDesign.ColorTheme or constructed using WireDesign.BaseColorPalette.
• New UI elements have Accessibility strings for VoiceOver.

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
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]

Test Results

  1 files  132 suites   30s ⏱️
483 tests 483 ✅ 0 💤 0 ❌
484 runs  484 ✅ 0 💤 0 ❌

Results for commit 9059bbd.

Summary: workflow run #22091249955
Allure report (download zip): html-report-27873-fix_WPB-23426-mls-decrypted