Problem

When we set a coder_app icon to a nonexistent path Coder dashboard is not able to render the icon and instead shows something like the image below.

This can happen when a coder module with a coder_app using a built in icon is used with an older Coder deployment not having that icon.

For example the cursror module icon is added to main but is not available in any Coder release yet.

Suggested solution

When the icon is set to a non existent icon let us skip rendering and it only show the display_text.