500 Map back end continuous-metadata endpoint throws 500 in no-data scenario

[bobular]

The following scenario causes a 500 on the back end. I think the subset is non-empty (there are no filters) but there's no data for the marker variable in that time range. The variable is prevalence of wild-type Kdr L1014 in the megastudy.

Originally posted by @bobular in https://github.com/VEuPathDB/web-monorepo/issues/868#issuecomment-1949102722

Here is the POST data

{
    "config": {
        "metadata": [
            "binRanges"
        ],
        "variable": {
            "entityId": "OBI_0000435",
            "variableId": "EUPATH_0043178"
        }
    },
    "filters": [
        {
            "entityId": "OBI_0000659",
            "max": "1998-04-23T00:00:00Z",
            "min": "1987-09-14T00:00:00Z",
            "type": "dateRange",
            "variableId": "EUPATH_0043256"
        }
    ],
    "studyId": "VBP_MEGA"
}