lnwallet+peer: remove unnecessary MaxPendingAmount method

We don't need this method, as we can directly access it from the peer
via public fields with its current usage.

lnwallet/channel.go

@@ -6336,9 +6336,3 @@ func (lc *LightningChannel) RemoteCommitHeight() uint64 {
 func (lc *LightningChannel) FwdMinHtlc() lnwire.MilliSatoshi {
 	return lc.localChanCfg.MinHTLC
 }
-
-// MaxPendingAmount returns the maximum HTLC value that can be pending at
-// any time over this channel.
-func (lc *LightningChannel) MaxPendingAmount() lnwire.MilliSatoshi {
-	return lc.localChanCfg.MaxPendingAmount
-}