rpc: display HTLC amount in satoshis in ListChannels response

Before this commit, they were displayed in mSAT which violates the
current trend of always displaying amounts externally in satoshis.

rpcserver.go

@@ -1337,7 +1337,7 @@ func (r *rpcServer) ListChannels(ctx context.Context,
 		for i, htlc := range localCommit.Htlcs {
 			channel.PendingHtlcs[i] = &lnrpc.HTLC{
 				Incoming:         htlc.Incoming,
-				Amount:           int64(htlc.Amt),
+				Amount:           int64(htlc.Amt.ToSatoshis()),
 				HashLock:         htlc.RHash[:],
 				ExpirationHeight: htlc.RefundTimeout,
 			}