Update UMO background radius to match UMO

Currently the background radius is less than the radius of the actual
UMO, which means the background is visible at the edges of the UMO.

Fixes: 393417466
Test: manually by playing media and opening GH
Flag: EXEMPT bugfix
Change-Id: Ib93fc7400173fcc8137e43df26917b2c0f6199ba