Misc Chat fixes

• fix chat back button size to make it easier to hit (especially on mobile)
• fix chat notifications being marked as read too eagerly, I've had the problem where I've missed quite a few chat messages because they arrive roughly at the same time as I'm leaving the chat view, so it has just enough time to register the messages as read but I didn't have enough time to even notice the new messages. Note that there was some double logic in how things get marked as read, that's why some "forceRead" calls were cut out, it still works like you'd expect.
• fix promiseinterval erroring when not getting a promise
• fix an error about lastMessage not having an account property, this was because of a typo with "account.id" instead of "account_id"