Previously, contact shares would be displayed as "Media Message". Now
it'll show the same as it does in a notification, namely
"{contact-emoji} {contact-name}".
The "contact" option in the attachments tray now brings you through an
optimized contact sharing flow, allowing you to select specific fields
to share. The contact is then presented as a special message type,
allowing you to interact with the card to add the contact to your system
contacts, invite them to signal, initiate a signal message, etc.
