Creating exhibit with repeated name crashes the frontend.

[pablodiegoss]

Describe the bug The Exhibit name is a unique field that crashes the page if you try to publish another one with the repeated name

To reproduce the bug

1. Upload an object
2. Upload a marker
3. Create an artwork using both marker and objects that you uploaded.
4. Create an exhibit with the name "Teste"
5. Create another exhibit with the name "Teste" again.

Expected behavior Show a message "This name is already taken, choose another one." Screenshots

[brenno-silva]

Since the others pull requests are stalled, can I give a try?