If the permission dialog would stick out, move it.

Also scroll the whole dialog if the screen is too small to for the
dialog.

Test: Executed steps in the bug. Dialog looks fine. Also toyed around
with display scaling and font scaling to make sure dialog always looks
ok (but might scroll) on very small displays.
Fixes: 31442798
Change-Id: I74328afde38ec2170a14aaa8e77675ad2164460e