Allow data field in error to be optional and skip validation if present

[kclowes]

The JSON-RPC spec states about the data field in an Error object:

This may be omitted.
The value of this member is defined by the Server

So I think we shouldn't validate that data is present or not in hive, and I also think we shouldn't validate that the errors need to be the same. This will help some tests to pass - for example in Reth:

• debug_getRawBlock/get-invalid-number (reth_default)
• debug_getRawHeader/get-invalid-number (reth_default)
• debug_getRawReceipts/get-invalid-number (reth_default)

[fjl]

But the data is important. What Reth does is wrong. They emit an error message in error.message and another one in error.data.

<<  {"jsonrpc":"2.0","id":1,"error":{"code":-32602,"message":"Invalid params","data":"hex string without 0x prefix at line 1 column 3"}}

The data field of the error is supposed to give machine-readable details about the error. For example, with the new error code 3, we use the data field to return the EVM return value to the caller so it can access the contract error. We definitely want to standardize what servers return in data.

[kclowes]

So you think if it's there it should be validated? Or that all of these types of responses have to contain a data field, and be validated?