feat: handle edited composite messages - WPB-19101

[caldrian]

WPB-19101 [iOS] Support editing a Composite message

Issue

Until now MessageEdit with a Composite item message types have been ignored, only Text has been handled.
Now with poll on MLS we started using them for dynamically updating the poll's results.

This PR handles messages of type MessageEdit with a Composite item.

Testing

Use the new Poll app in an MLS conversation.

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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.

[github-actions]

Test Results

    2 files    421 suites   2m 19s ⏱️
2 300 tests 2 273 ✅ 27 💤 0 ❌
2 301 runs  2 274 ✅ 27 💤 0 ❌

Results for commit 7429d1c.