Attempt to find the keyboard by traversing the view hierarchy if it was not found

In certain situations (i.e. creating UI in code), the keyboard was only found on the second "drag".

This PR adds a second line of defense if the keyboard wasn't found through the `inputAccessoryView `.

If you're hesitant, let me know and I'll show you an example in which the original code doesn't work but this one does.

Thanks for the great code!