fix(course): 捕获getHTML请求异常并返回null

当请求失败时，捕获异常并打印错误日志，避免程序中断

src/services/course.ts

@@ -84,7 +84,10 @@ export const selectWorksStudent = (oid: string, cid: string): Promise<any> => {
  * @returns Promise<any>
  */
 export const getHTML = (url: string): Promise<any> => {
-  return axios.get(`${url}`)
+  return axios.get(`${url}`).catch((error) => {
+    console.error('getHTML 请求失败:', error)
+    return null
+  })
 }
 
 /**