Unstructured errors returned from query RPC method

[miraclx]

Describe the bug

Following #3944, the process_query_response method was introduced to maintain backwards compatibility when reporting some variants of QueryError.

nearcore/chain/jsonrpc/src/lib.rs

Lines 129 to 131 in 78c4b0c

	/// This function processes response from query method to introduce
	/// backward compatible response in case of specific errors
	fn process_query_response(

The implication of this, is that, instead of the server returning structured errors in the VErr format (#2976), it returns a custom JSON response with the error contained inside a string. And worse of all, under the guise of a "result" instead of an "error".

// $ http ... method=query params='{"request_type":"view_access_key","account_id":"test.near","public_key":"..."}'
{
    "jsonrpc": "2.0",
    "result": { // <-- returns "result" instead of "error"
        "block_hash": "HZUfyFnKD8uneRDc8LYWe2xxMWFBYj2oxes3iZuwYAPX",
        "block_height": 84145708,
        "error": "access key ed25519:J9rU3yZhwZB3UriwvETEcuf1a7FyS3sz5sTsmH2z8zTe does not exist while viewing",
        "logs": []
    },
    "id": "dontcare"
}

Expected behavior

I personally feel we should migrate totally off unstructured server responses and have something to the effect of:

// $ http ... method=query params='{"request_type":"view_access_key","account_id":"test.near","public_key":"..."}'
{
    "jsonrpc": "2.0",
    "error": {
        "name": "HANDLER_ERROR",
        "cause": {
            "info": {
                "public_key": "ed25519:J9rU3yZhwZB3UriwvETEcuf1a7FyS3sz5sTsmH2z8zTe",
                "block_height": 84145708,
                "block_hash": "HZUfyFnKD8uneRDc8LYWe2xxMWFBYj2oxes3iZuwYAPX"
            },
            "name": "UNKNOWN_ACCESS_KEY"
        },
        "code": -32000,
        "message": "Server error",
        "data": "access key ed25519:J9rU3yZhwZB3UriwvETEcuf1a7FyS3sz5sTsmH2z8zTe does not exist while viewing"
    },
    "id": "dontcare"
}

Additional context

The extended impact of this, is, on near-jsonrpc-client, when deserializing the server response back into the RpcQueryError structure, it fails from attempting to parse the unstructured data the server responds with.

cc: @frol @khorolets