Editor inserts new line break when inserting heading

Issue Summary

Inserting a "heading line" inside a table is inserting additional "line breaks".

Steps to Reproduce

1. Create a page with the following storage format

   <table>
   <colgroup>
   <col />
   <col />
   </colgroup>
   <tbody>
   <tr>
   <th scope="col"><br /></th>
   <th scope="col"><br /></th>
   </tr>
   <tr>
   <td>
   <div class="content-wrapper">
   <p><time datetime="2024-04-24" /> </p>
   </div>
   </td>
   <td>
   <div class="content-wrapper">
   <p><time datetime="2024-04-11" /> </p>
   </div>
   </td>
   </tr>
   </tbody>
   </table>
   

   • Save the page
     
2. Edit the page and place the cursor before the first date value
   • Add a "Heading 6"
   • Publish the page

Expected Results

In an unaffected Confluence version:

The storage format does not add "new line breaks"

<table class="wrapped"><colgroup> <col /> <col /> </colgroup>
<tbody>
<tr>
<th scope="col"><br /></th>
<th scope="col"><br /></th></tr>
<tr>
<td>
<div class="content-wrapper">
<h6><time datetime="2024-04-24" /></h6></div></td>
<td>
<div class="content-wrapper">
<p><time datetime="2024-04-11" /></p></div></td></tr></tbody></table>

Actual Results

New lines are inserted:

The new page storage format has added line breaks :

<table class="wrapped"><colgroup> <col /> <col /> </colgroup>
<tbody>
<tr>
<th scope="col"><br /></th>
<th scope="col"><br /></th></tr>
<tr>
<td>
<div class="content-wrapper">
<p><br /></p>
<h6><time datetime="2024-04-24" /></h6>
<p><br /></p></div></td>
<td>
<div class="content-wrapper">
<p><time datetime="2024-04-11" /></p></div></td></tr></tbody></table>

Workaround

Edit the page and manually remove any unwanted line breaks.