Remove UgBgGroupThrottle node to keep ug_bg_group_throttle 308 by default am: 3eb0dc523f am: 1402f63109 am: be67e3af5b am: 43570b9d47

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

Change-Id: Icfd701a7b0e6541fba34ae8cdf5ad5d5e426126e
Signed-off-by: Automerger Merge Worker <[email protected]>