fix lint and unit test errors

Author: Péter Garamvölgyi

encoding/codecv7_types.go

@@ -259,6 +259,9 @@ func (b *blobPayloadV7) Encode() ([]byte, error) {
 
 		// encode L2 txs as RLP and append to transactionBytes
 		for _, txData := range block.Transactions {
+			if txData.Type == types.L1MessageTxType {
+				continue
+			}
 			rlpTxData, err := convertTxDataToRLPEncoding(txData)
 			if err != nil {
 				return nil, fmt.Errorf("failed to convert txData to RLP encoding: %w", err)

encoding/da.go

@@ -255,6 +255,7 @@ func convertTxDataToRLPEncoding(txData *types.TransactionData) ([]byte, error) {
 		})
 
 	case types.L1MessageTxType: // L1MessageTxType is not supported
+		fallthrough
 	default:
 		return nil, fmt.Errorf("unsupported tx type: %d", txData.Type)
 	}
@@ -789,7 +790,7 @@ func MessageQueueV2ApplyL1MessagesFromBlocks(initialQueueHash common.Hash, block
 	return rollingHash, nil
 }
 
-func messageQueueV2ApplyL1Messages(initialQueueHash common.Hash, messages []*types.L1MessageTx) common.Hash {
+func MessageQueueV2ApplyL1Messages(initialQueueHash common.Hash, messages []*types.L1MessageTx) common.Hash {
 	rollingHash := initialQueueHash
 	for _, message := range messages {
 		rollingHash = messageQueueV2ApplyL1Message(rollingHash, message)