Skip shelf icon fade for low priority notifications

Fix issue where low priority icons fade into the shelf
then immediately fade out into the dot.

Remove unused things

- openedAmount: originally added to fix cutout issue
  but we won't show the shelf near the cutout anymore

- expandedAmount: tweaks shelf transformation near the status bar
  but we won't show the shelf near the status bar anymore

- handleCustomTransformHeight: leftover from shelf-icon to notif-icon
  animation, which we already removed

Bug: 178479515
Test: scroll shade up and down
Change-Id: I7c3e2cb6dac1ce70de1dbe575734c393f7f511de