Update AccountCreationAuth & fix auth.HashToSign

- Fix AccountCreationAuth.HashToSign (was using `[]byte("0x...")`, which
uses the bytes of the string. Now uses the bytearray of the compressed
BJJ public key (compatible with js implementation))
- Update AccountCreationAuth to last specification (add to hash
parameters ChainID & HermezAddress)
- Add missing test to AccountCreationAuth

api/config_test.go

@@ -9,7 +9,7 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
-func getConfigTest() Config {
+func getConfigTest(chainID uint16) Config {
 	var config Config
 
 	var rollupPublicConstants common.RollupConstants
@@ -40,6 +40,9 @@ func getConfigTest() Config {
 	config.AuctionConstants = auctionConstants
 	config.WDelayerConstants = wdelayerConstants
 
+	config.ChainID = chainID
+	config.HermezAddress = ethCommon.HexToAddress("0xc344E203a046Da13b0B4467EB7B3629D0C99F6E6")
+
 	return config
 }