code_review/performance: gjson.ParseBytes call twice in rsp json parsing cause extra performance cost should use json.RawMessage

[pymongo]

current json rpc response code performance is poor

https://github.com/block-vision/sui-go-sdk/blob/c2c872d55fef3a9a42dec800f089373f29781302/sui/read_transaction_api.go#L55-L61

bad performance points:

• gjson.ParseBytes(respBytes) call twice (go compiler may not optimize to call once)
• gjson.ParseBytes would parse whole json to map[string]interface{} recursive

I provide a better_performance/much_faster code demo, benifit:

• json.RawMessage just a string(lazy parsing), if response json has error would not parsing whole json
• if no error second marshel Result field string to resp json instead of gjson.ParseBytes whole json

	type rpcRsp struct {
		Error  string          `json:"error,omitempty"`
		Result json.RawMessage `json:"result,omitempty"`
	}
	var r rpcRsp
	err = json.Unmarshal(respBytes, &r)
	if err != nil {
		return rsp, nil
	}
	if r.Error != "" {
		return rsp, errors.New(r.Error)
	}
	err = json.Unmarshal(r.Result, &rsp)
	if err != nil {
		return rsp, nil
	}