feat: improved e2e tests

frontend/app/cypress/integration/opening-hours.spec.ts

@@ -1,8 +1,16 @@
 describe('opening hours', () => {
   beforeEach(function () {
-    cy.intercept('POST', 'https://mobile.server.uni-frankfurt.de/search', {
-      fixture: 'search/types/canteen/canteen-search-result.json',
-    }).as('search');
+    cy.interceptSearch({
+      extends: 'canteen/all',
+      fixture: 'canteen/all',
+      alias: 'search',
+    });
+    cy.interceptMultiSearch({
+      extends: 'canteen/dishes',
+      fixture: 'canteen/dishes',
+      alias: 'dishes',
+    });
+    cy.clock().invoke('restore');
   });
 
   it('should specify relative closing time', () => {