fix: establish groups pending join if epoch is 0 - WPB-22496 🍒 🍒

[github-actions]

This PR was automatically cherry-picked based on the following PR:

• fix: establish groups pending join if epoch is 0 - WPB-22496 🍒 #4044

Original PR description:

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WPB-22496 [iOS] Don't join pending group via external commit if epoch is 0

Issue

Cherry pick of #4034

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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.

[zenkins]

✅ Auto-approved cherry-pick PR 🍒.

[github-actions]

Test Results

2 372 tests   2 372 ✅  4m 19s ⏱️
  242 suites      0 💤
    1 files        0 ❌

Results for commit f2a0891.