Set HolderCommitmentPoint::current_point on read

When introducing HolderCommitmentPoint::current_point, the value was
mistakenly not set when read except in the legacy case where the next
point needed to be fetched. But in that case, it would have been read as
None given it is a new field.

Author: jkczyz

lightning/src/ln/channel.rs

@@ -13841,7 +13841,7 @@ where
 			match (holder_commitment_point_next_opt, holder_commitment_point_pending_next_opt) {
 				(Some(next_point), pending_next_point) => HolderCommitmentPoint {
 					next_transaction_number: holder_commitment_next_transaction_number,
-					current_point: None,
+					current_point: holder_commitment_point_current_opt,
 					next_point,
 					pending_next_point,
 				},