Actually use the height specified on bubble metadata

* Lowers default size based on desires of UX
  -> still allows a larger size for 'contentIntent' based bubbles so that
     things forced into a bubble are still reasonably useable
* Ensures the height for activity view will fit on the screen based on
  the position the bubbles expand to and the space needed for the dismiss
  target

Test: manual / with Bubble app adjusted to have a height slider
Bug: 123961288
Change-Id: I31fc31d78fc51ce261ec8d693b4e18cff867ef0d