refactor(app): 优化邮件模板

app/Http/Controllers/Mobile/CourseController.php

@@ -804,7 +804,7 @@ class CourseController extends CommonController
             $list = $list->orderBy('letter')->paginate(20);
         }
         // 获取当前用户参与报名
-        $userCourseSigns = $this->getUser()->courseSigns->where('status', 1)->get();
+        $userCourseSigns = CourseSign::where('user_id',$this->getUserId())->where('status', 1)->get();
         // 获取当前用户允许的课程体系
         $open_course_types = explode(',', $this->getUser()->open_course_types);