internal/ethapi: fix recover sender of pending transaction (#23765)

* internal/ethapi: fix recover sender of pending transaction

* internal/ethapi: check if current exists

internal/ethapi/api.go

@@ -1334,10 +1334,12 @@ func newRPCTransaction(tx *types.Transaction, blockHash common.Hash, blockNumber
 // newRPCPendingTransaction returns a pending transaction that will serialize to the RPC representation
 func newRPCPendingTransaction(tx *types.Transaction, current *types.Header, config *params.ChainConfig) *RPCTransaction {
 	var baseFee *big.Int
+	blockNumber := uint64(0)
 	if current != nil {
 		baseFee = misc.CalcBaseFee(config, current)
+		blockNumber = current.Number.Uint64()
 	}
-	return newRPCTransaction(tx, common.Hash{}, 0, 0, baseFee, config)
+	return newRPCTransaction(tx, common.Hash{}, blockNumber, 0, baseFee, config)
 }
 
 // newRPCTransactionFromBlockIndex returns a transaction that will serialize to the RPC representation.