LTS Refresh: Merge upto 3fb84885ff2d818b475093dc9c9d10dc33ee7622 (buildnumber: 18867.90.0) from main-R121-cos-6.6 to release-R121-cos-6.6.

BUG=b/411674189,b/403143870,b/398906385
TEST=presubmit
RELEASE_NOTE=LTS Refresh from main-R121-cos-6.6 to release-R121-cos-6.6

Change-Id: I9739043cb91cd8cda5b4e63ad1100b83a54b82ca