Remove delivery spinners entirely

[quinthar]

let's not show the spinner after sending a message because it highlights how long it takes for the message to actually be delivered, whereas it would be nicer if it were presented as if instantaneous and only show that it wasn't delivered in the event there is some kind of error

[quinthar]

Incidentally, the spinners seem broken to me anyway; they never stop spinning, even though the message was delivered. So I suggest for now, the critical thing is to just remove the spinners entirely. I'll create a second issue to add a "queued" indicator for messages that can't be delivered (either due to network error, or being written while offline)