[QSDetailedView] Fix the bt details progress bar issue

There's no need to add the progress bar backgroud in the
details view. This cl removed it. Now when we hide the
progress bar, it will go away.

Bug: 429237908
Flag: com.android.systemui.qs_tile_detailed_view
Test: UI change only. Existing unit tests still pass.
Change-Id: I064746c74d39e4f3c355e86d9a57f56ec7ee66f9