test(products): increase test timeout for category update

- Set Jest timeout to 15 seconds for products.update-category.http.spec.ts
- Ensures reliable execution of category update integration tests

BREAKING CHANGE: None

backend/src/products/products.update-category.http.spec.ts

@@ -13,6 +13,8 @@ import { CategoriesService } from '../categories/categories.service';
 import { ProductsController } from './products.controller';
 import { ProductsService } from './products.service';
 
+jest.setTimeout(15000);
+
 class FakeJwtGuard implements CanActivate {
   canActivate(context: ExecutionContext): boolean {
     const req = context.switchToHttp().getRequest();