Fix rest test when numShards is greater than 1 (#35909)

modules/lang-painless/src/test/resources/rest-api-spec/test/painless/30_search.yml

@@ -464,6 +464,7 @@
         catch: bad_request
         search:
             index: test
+            allow_partial_search_results: false
             body:
                 query:
                     function_score: