Allow blurred background to be seen behind notification badge icon

This will change the badge ring from a flat color to a transparent
cutout showing the blurred notification background.

Test: Tested on the device
Fixes: b/409346132
Flag: com.android.internal.widget.flags.notification_transparent_badge_ring
Change-Id: Ic82b038530a80ea7dbc2aadc4b99ab559ffd6f58