fix(接口测试): 修复接口测试另存为用例的缺陷

--bug=1037918 --user=宋天阳  https://www.tapd.cn/55049933/s/1484242

frontend/src/views/api-test/components/requestComposition/index.vue

@@ -1481,6 +1481,9 @@
         } finally {
           saveCaseLoading.value = false;
         }
+      } else {
+        saveCaseLoading.value = false;
+        done(false);
       }
     });
   }