blank lines disappear #3302

Describe the Bug

Empty lines disappear after saving page.

Steps to Reproduce

1. In the WYSIWYG editor, write two paragraphs with blank lines in between, like this (use "Enter" key)
   

2.Click save, then the page will display normally.

3.Edit the page again without changing anything, then save.

4.blank lines disappeared.

Expected Behaviour

Blank lines are normally retained.

Screenshots or Additional Context

This can be reproduced in the demo site.
https://demo.bookstackapp.com/books/dummy-content-book/page/new-page

Browser Details

Chrome 8.0.4758.102 64bit Win10

Exact BookStack Version

BookStack v22.02.1

PHP Version

demo site

Hosting Environment

demo site