fix: update post_cell function to handle different newline characters in cell values

[shaohuzhang1]

fix: update post_cell function to handle different newline characters in cell values --bug=1054683 --user=刘瑞斌 【github#2831】知识库上传excel、应用编排文档内容提取节点中上传excel，单元格中有换行，导入后没有在一个单元格里显示 https://www.tapd.cn/57709429/s/1690232

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[shaohuzhang1]

The provided code is mostly correct but has a small issue with handling line breaks (\t):

@@ -14,7 +14,7 @@
 
 
 def post_cell(cell_value):
-    return cell_value.replace('\n', '<br>').replace('|', '&#124;')
+    return cell_value.replace('\r\n', '<br>').replace('\n', '<br>').replace('\t', '&nbsp;')  # Add this line to replace tabs with spaces

Explanation:

1. Replacement of \n: Both \n and \r\n are used to denote line breaks in text. By replacing both \n and \r\n, you ensure consistency across different newline characters.

2. Handling Tabs: The code currently replaces tabs (`\t) with  ` (non-breaking space). This may be necessary if tabular data needs to preserve its original formatting, especially when converting it to HTML or Markdown where automatic indentation might cause problems.

3. Potential Issues:

   • If the input data contains only \ts without any newlines, post_cell will not work as intended because it relies on \n.
   • Ensuring that all relevant whitespace characters (including tabs) are handled appropriately can make the function more robust for various inputs.

By adding the replacement for \t, you handle more edge cases and ensure that the converted markup preserves consistent spacing and structure.