Can't edit comments

[ane-gabriela]

Steps to reproduce:

1. Click on a forum

2. Click on a topic

3. Edit a comment - green pencil
   

4. Make some changes

5. Save comment

Expected results: The comment can be edited.

Actual results: After clicking the Edit icon a grey box appears without the text that should be editable. Only information about the user that created the comment appears.

Environment: XWiki 12.6.1 with MySQL 8.0, Edge 84 and Forum Application (Pro) 2.7.3

[ane-gabriela]

Reproduce on 12.6.2 also