Some Ion imagery assets attempt to load from localhost instead of the correct URLs

As identified on the forums, Cesium for Unity (and potentially all cesium-native clients) attempts to load some Ion imagery overlays from the incorrect URLs. For example, for asset 2411391, the request to the Ion endpoint gives:

{
    "type": "IMAGERY",
    "externalType": "BING",
    "options": {
        "url": "//dev.virtualearth.net",
        "mapLayer": "Foreground",
        "mapStyle": "AerialWithLabelsOnDemand",
        "key": "<key removed>"
    },
    "attributions": [...]
}

Based on this information, Cesium for Unity should calculate the URL https://dev.virtualearth.net/REST/v1/Imagery/Metadata/AerialWithLabelsOnDemand?incl=ImageryProviders&key=<key removed>&uriScheme=https, as CesiumJS does. Instead it tries to make a request for the URL http://localhost/REST/v1/Imagery/Metadata/AerialWithLabelsOnDemand?incl=ImageryProviders&key=<key removed>&uriScheme=https, which obviously fails.

CesiumGS / cesium-unity

Some Ion imagery assets attempt to load from localhost instead of the correct URLs #455