contractcourt: update breach arbiter to support taproot chans

In this commit, we update the breach arb to support taproot channels. We
utilize the new taproot briefcase space to store both control blocks,
and also the first+second level scripts for the set of HTLCs.

contractcourt/chain_watcher.go

@@ -881,9 +881,6 @@ func (c *chainWatcher) handlePossibleBreach(commitSpend *chainntnfs.SpendDetail,
 	}
 
 	// Create an AnchorResolution for the breached state.
-	//
-	// TODO(roasbeef): make keyring for taproot chans to pass in instead of
-	// nil
 	anchorRes, err := lnwallet.NewAnchorResolution(
 		c.cfg.chanState, commitSpend.SpendingTx, retribution.KeyRing,
 		false,