Motivation
We are getting failures in hive tests due to the formatting of the storage values in etc_getStorageAt ie:

[16a390f6] <<  {"id":1,"jsonrpc":"2.0","result":"0x1c"}
[16a390f6] response differs from expected (-- client, ++ test):
[16a390f6]  {
[16a390f6]    "id": 1,
[16a390f6]    "jsonrpc": "2.0",
[16a390f6] -  "result": "0x1c"
[16a390f6] +  "result": "0x000000000000000000000000000000000000000000000000000000000000001c"
[16a390f6]  }

Description

• Convert storage values from U256 to H256 before serializing them to ensure the correct format is shown in rpc endpoint eth_getStorageAt

Closes None, but fixes formatting issues in hive tests for eth_getStorageAt