feat:处理选择文件列表不能翻页的问题

src/modules/prepare-lesson/modal/SelectPrepareFileModal.jsx

@@ -288,7 +288,8 @@ class SelectPrepareFileModal extends React.Component {
     const hasMore = folderList.length < totalCount;
 
     const { fileListRef } = this.refs;
-    const hasReachBottom = fileListRef.scrollTop + fileListRef.clientHeight === fileListRef.scrollHeight;
+    // const hasReachBottom = fileListRef.scrollTop + fileListRef.clientHeight === fileListRef.scrollHeight;
+    const hasReachBottom = fileListRef.scrollTop + fileListRef.clientHeight > fileListRef.scrollHeight - 1;
     if (!hasReachBottom || !hasMore) return;
     
     const currentFolder = folderPathList[folderPathList.length - 1];