unified-storage: restrict search to title of documents (#111842)

* restrict search to title of documents

pkg/storage/unified/testing/search_backend.go

@@ -164,14 +164,18 @@ func runTestResourceIndex(t *testing.T, backend resource.SearchBackend, nsPrefix
 					Group:     ns.Group,
 					Resource:  ns.Resource,
 				},
+				Fields: []*resourcepb.Requirement{{
+					Key:      "tags",
+					Operator: "=",
+					Values:   []string{"tag3"},
+				}},
 			},
 			Fields: []string{"title", "folder", "tags"},
-			Query:  "tag3",
 			Limit:  10,
 		}, nil)
 		require.NoError(t, err)
 		require.NotNil(t, resp)
-		require.Equal(t, int64(1), resp.TotalHits) // Only doc3 should have tag3 now
+		require.Equal(t, int64(1), resp.TotalHits) // Only doc2 should have tag3 now
 
 		// Search for Document
 		resp, err = index.Search(ctx, nil, &resourcepb.ResourceSearchRequest{