CQL_FILTER for CesiumWebMapServiceRasterOverlay with Cesium for Unity

### Feature

I need to use CQL_FILTER to filter a WMS layer but this option is not available using Cesium for Unity's CesiumWebMapServiceRasterOverlay for now. Are there any workarounds for this problem?

For example below is a figure of how one would use GeoServer and CQL_FILTER to filter a WMS layer and have that filter update immediately, on GeoServer, after querying. The image is obtained from GeoServer's CQL documentation: https://docs.geoserver.org/2.27.x/en/user/tutorials/cql/cql_tutorial.html.

Is it possible to query a WMS layer and see that WMS layer change right away in response to our CQL query, in Cesium for Unity, like how GeoServer behaves?