I clicked the play button for which I chose my device from Xcode. The imulator launched and showed a representation of my iPhone X device. I looked out my iPhone's iMessage. Take a look my attachment here. AppIcon has no image.
I viewed iMessage's settings that my app's AppIcon looks fine and working. But keyboard's AppIcon doesn't show an image. I am confused.
I put all the required imessage icons in Assets and double checked that there sizes are proper as required.