Update BubbleExpandedView inset & height

The inset code for the IME would be too big if there was a notch. This CL
changes the displaySize to be the "real" displaySize, which makes
calculations more obvious & fixes notch issue.

Fixes an issue where the max height of the view was subtracting the
"manage" button height twice. Also subtracts the bottom inset from max
height since we're using the "real" display size.

Removes some obsolete code that was needed when bubbles were at the bottom,
this fixes a weird animation glitch with the height when expanding bubbles.

Fixes: 139002444
Test: manual - expand a bubble, make it max height, focus the IME
             - repeat above with all the different notch configurations
               in developer options
             - also toggle the different nav options (navbar & gesture)

Change-Id: I59e60864369d1bd3a15480c56b7b3fbe98b2fc16