sweep: allow specified outputs to sweep tx

We'll use this to attach an output for the value reserved for anchor
commitments fee bumping if the user requests a send_all transaction.

rpcserver.go

@@ -1256,7 +1256,7 @@ func (r *rpcServer) SendCoins(ctx context.Context,
 		// safe manner, so no need to worry about locking.
 		sweepTxPkg, err := sweep.CraftSweepAllTx(
 			feePerKw, lnwallet.DefaultDustLimit(),
-			uint32(bestHeight), targetAddr, wallet,
+			uint32(bestHeight), nil, targetAddr, wallet,
 			wallet.WalletController, wallet.WalletController,
 			r.server.cc.FeeEstimator, r.server.cc.Signer,
 		)