contractcourt: extend the ChainArbitratorConfig with IsOurAddress closure

In this commit, we add the IsOurAddress field into the config of the
chain arb. With this new function closure, the chain arb is able to
detect co-op on chain closes automatically.

server.go

@@ -400,6 +400,10 @@ func newServer(listenAddrs []string, chanDB *channeldb.DB, cc *chainControl,
 			chanID := lnwire.NewChanIDFromOutPoint(&chanPoint)
 			return s.htlcSwitch.RemoveLink(chanID)
 		},
+		IsOurAddress: func(addr btcutil.Address) bool {
+			_, err := cc.wallet.GetPrivKey(addr)
+			return err == nil
+		},
 	}, chanDB)
 
 	s.breachArbiter = newBreachArbiter(&BreachConfig{