Create custom response dataclasses for our endpoints

[odjuricicTT]

On the backend for perf_data overlay we inject this data into the model explorer graph object and send the object to the frontend. So the response looks something like this:

{
    "graphs": [
        {
            <graph_fields>,
            "perf_data": ...
        }
    ]
}

The proper way to do this would be to create our own response dataclasses and use for our endpoints. Have the response look something like:

{
    "graphs": [
        {
            <graph_fields>
        }
    ],
    "perf_data": ...
}