It's not possible to provide a default search_view config without overriding the one used in AdminUI.

Steps to reproduce:

1. In config/packages/ezplatform.yaml provide the following configuration:

   parameters:
       ezsettings.default.search_view:
           full:
               default:
                   template: "@@ezdesign/search/index.html.twig"
                   match: []
   

1. (clear cache if needed)
2. Login as admin
3. Go to Content -> Content Structure -> Search

Expected:

Search is working as always - we've only provided the default, fallback configuration.

Actual:

Search fails to load with:

 Neither the property
 "search_in_users" nor one of the methods "search_in_users()", 
"getsearch_in_users()"/"issearch_in_users()"/"hassearch_in_users()" or 
"__call()" exist and have public access in class 
"Symfony\Component\Form\FormView".

as if we've overridden the AdminUI config.