fix:修复新建图片显示功能

src/views/CourseSquare/component/CourseDetails/index.vue

@@ -7,7 +7,7 @@
   <div class="course-details">
     <div class="course-details-info">
       <div>
-        <img  class="course-details-image" :src="convertImageUrl(dataForm.courseImages[0], dataForm.courseName)" :alt="dataForm.courseName">
+        <img  class="course-details-image" :src="convertImageUrl(dataForm.courseImages == null ? null : dataForm.courseImages[0], dataForm.courseName)" :alt="dataForm.courseName">
       </div>
       <div class="course-details-text">
         <div class="title">