Voice messages: Persist drafts of voice messages when navigating between rooms

[jakewb-b]

• Leaving a room stops recording but saves the draft.
• On going to any other room, the user can send messages as normal. But on returning to the room where they were recording a message, the draft will remain in place ready to be sent.
• The draft should look and behave the same as an unsent voice message if I had stopped recording but stayed in the room.
• 
• I cannot edit or continue recording the voice message at this stage.
• The only choices are delete, play/preview or send
• It is also not possible to send another message in this room until you have either deleted or sent the draft voice message.
• It is possible to have multiple draft voice messages in multiple rooms. The draft only appears when I go to the relevant room.