"Temporarily" removed progress check.

The code that asserts the right progress is displayed was based on the
percentage text displayed in the system notification, but such text is
gone.

Since UIObject doesn't easily expose the underlying ProgressBar, such
checks were temporarily disabled.

BUG: 28114251
Change-Id: Idb64fe97cf84f5f73e08e293b8fd0384bc8b70d6