fix: preserve group permission flags on metadata edit

[barrydeen]

Summary

• Bug: editing group name, about, or picture caused all permission settings to reset to fully open
• Fix: updateMetadataOnRelay() now includes all four permission tags in the kind 9002 edit event
• The create flow already did this correctly; now the edit flow matches

Changes

• GroupListViewModel.kt: added permission tag generation in updateMetadataOnRelay() mirroring createGroup() logic

Testing

• Built successfully with gradle assembleDebug
• Manually tested in-app

Clanked locally with Qwen3.6 and OpenCode