Remove UgBgGroupThrottle node to keep ug_bg_group_throttle 308 by default am: 3eb0dc523f am: 9c8844e266 am: 4d1add1061 am: 145d7344dc

Original change: https://googleplex-android-review.googlesource.com/c/device/google/lynx/+/23672755

Change-Id: Ifa7fda42ce90c75774e003b56e66c11173333943
Signed-off-by: Automerger Merge Worker <[email protected]>