Merge "Add KeepalivePacketData toString()" am: c05d86b850 am: 83e1ca472e am: d1d281e709

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/1982947

Change-Id: I099b08f2e20d1064b26ac44fde5e49f5c4862a03