Provide Legend Labels for Stretch Map Image Raster

[NickWeil]

I am in the process of publishing several raster layers to my portal for use in a web mapping application. The layers are being published as a Map Image that is copied to the server.  I am struggling because I want some legend information included in my App, but because I am using a stretch symobology on the raster, it does not include labels.

Here is the symbology in ArcGIS Pro before publishing:

Once published, it appears the label information is forgotten and my Web App legend will only display this:

Does anyone know of a way to include legend information in this situation?