Merge "Add RtmNetlinkPrefixMessage class to represent RTM_NEWPREFIX message." into main am: 7dd2525646 am: 1b99b824e9

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3039360

Change-Id: I62e743fb3103771604ca3657aee5d66d7aa6e294
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>