Shadow for bubble icons fixed.

The bubble's outline was hardcoded with a fixed size. This caused a
shadow to be drawn using the hardcoded outline size, regardless of the
actual bubble view size. The BubbleView logic has been updated to use
the actual bubble size for the outline. The guarding flag has been
removed.

Bug: 340445019
Flag: com.android.wm.shell.enable_bubble_bar
Test: http://recall/-/gx8ASgewUeUS3QYohfrd1J/hqFtAZJnX0tCRONoFpSK3i
Change-Id: Iaa2c2d0bfeee2af9840acbcf11daaf8be2e0b7af