Hi Fahad,
Normally, Filter can show descriptions for coded values.
You can try service Layer: Facilities (ID: 0)
Field facility has codedValue domain.
WAB can show the descriptions as the following screenshot.
Just as dlaw-esristaff said, this is a limition of ArcGIS Online hosted feature service. ArcGIS Online hosted feature service loses domain descriptions when you publish service.
You can publish a feature service by ArcGIS Server and have a try.