Track clat interface status via IpClientLinkObserver for accuracy

Leveraged IpClientLinkObserver.onClatInterfaceStateUpdate() to monitor
clat interface additions/removals, using RTM_NEWLINK/RTM_DELLINK
messages for accurate tracking.

Test: TH
Change-Id: I85c2a8d9e82803a82c1acc93b1fd062d56d520a1
3 files changed