List of users in a DM conversation, as a page

[gnprice]

When a DM conversation has many users in it, or their names are long, they might not all fit in the app bar. We should offer a page that lists all those users, reachable by tapping the app bar when looking at a DM conversation.

This page will also be reachable from the DM-conversation action sheet, which one can get by long-pressing a DMs item in the inbox, or an item in the DM-conversations page, etc., as listed at #F1272.

References

• Chat thread: #mobile > abbreviated headings @ 💬
• Figma design