Scroll up when keyboard appears, only when at the bottom.

[hidayetozsoy]

I'm aware of the property scrollsToLastItemOnKeyboardBeginsEditing, but it doesn’t fully meet my needs and, in my opinion, lacks intuitiveness. This property triggers a scroll to the bottom with every text change in messageInputBar.inputTextView. Consequently, when not at the very bottom of messagesCollectionView, it attempts to scroll down multiple times, which results in a less-than-ideal user experience. I believe adopting an approach similar to WhatsApp's, where the scroll view moves up by the keyboard's height, would be more intuitive. While I plan to implement this logic myself, it's challenging since MessageKit calculates the height of messageInputBar, so it might take me some time to work through. :)