filter-aware-metadata/continuous-variable is returning extra `value: null` in `binRanges.*`

[bobular]

The value prop is not in the spec and looks uniformly null. Working around in the client for now. Might be an EdaDataService or veupathUtils issue? I found where the dirty work is done ;-) but it's delegated to R https://github.com/VEuPathDB/EdaDataService/blob/master/src/main/java/org/veupathdb/service/eda/ds/plugin/filteredmetadata/ContinuousVariablePlugin.java#L98

{
    "equalInterval": [
        {
            "binEnd": "358.2",
            "binStart": "17",
            "value": null,
            "binLabel": "[17, 358.2]"
        },
        {
            "binEnd": "699.4",
            "binStart": "358.2",
            "value": null,
            "binLabel": "(358.2, 699.4]"
        },
        {
            "binEnd": "1040.6",
            "binStart": "699.4",
            "value": null,
            "binLabel": "(699.4, 1041]"
        },
        {
            "binEnd": "1381.8",
            "binStart": "1040.6",
            "value": null,
            "binLabel": "(1041, 1382]"
        },
// SNIPPED      
    ]
}

[d-callan]

toJSON method for the Bin class in veupathUtils must not be doing the right thing when value is NA

[d-callan]

fixed v2.2.3