TemplateDefinitionValidator produces false positives for missing template scripts:

• file system templates (outside of resource.dir, see templating-samples module)
  • JspRenderes uses info.magnolia.context.WebContext#include so the template is not fetched from the resource origin
• blossom templates (see blossom samples module)
  • The actual blossom template script will be the one returned by the controller

P.S
Please unignore DefinitionAppUITests when this issue is fixed. (Both CE and EE)