Validation should be shown whenever user tries to create same name imageset in GalleryManager

Steps to reproduce:
1.Start essentials archetype based project.
2.Go to GalleryManager in Tools
3.Add a new image set with name "myTest"
4.Try to add again new image set with same name "myTest".
5.Notice validation is not shown and error is logged in the console.

Expected:Textbox should be shown as red
Check screenshot for reference.