Search portlet breaks when searching for a misbehaving AssetEntry.
Steps to reproduce:
1) Login as admin
2) Go to control panel -> Content -> Forms -> create new form with any field (e.g., text field)
3) Add a Form portlet to a page
4) In the new Form portlet, select the form created in step 2 and save
5) Submit a new forms record in the Form portlet
6) From a search portlet, search for the form created in step 5 (using whatever was entered in the fields)
Expected result: the form record created is returned as a search result
Actual result: the error "Search is temporarily unavailable." appears and an error appears in the console.