Remove check if a block has its own tx as a payload spender since we …

…always fork on conflicts

This avoid re-encoding the transaction to calculate the ID

pkg/protocol/engine/booker/inmemorybooker/booker.go

@@ -225,7 +225,7 @@ func (b *Booker) inheritSpenders(block *blocks.Block) (spenderIDs ds.Set[iotago.
 
 			// Check whether the parent contains a conflicting TX,
 			// otherwise reference is invalid and the block should be marked as invalid as well.
-			if signedTransaction, hasTx := parentBlock.SignedTransaction(); !hasTx || !parentBlock.PayloadSpenderIDs().Has(signedTransaction.Transaction.MustID()) {
+			if _, hasTx := parentBlock.SignedTransaction(); !hasTx {
 				return nil, ierrors.Wrapf(err, "shallow like parent %s does not contain a conflicting transaction", parent.ID.String())
 			}