Remove HTML tags from locked fields

Issue Summary

Considering the goal to change the mark up from HTML to Wiki, we need also that locked fields are updated as well.

Steps to Reproduce

if you look at the screenshot of 8.11.1, the one with the red markings, you will see that the HTML in the Request Participants field is simply <p></p>.
These tags are completely unnecessary.

Expected Results

No HTML tags present in locked fields.

Actual Results

HTML tags present in locked fields.

Workaround

It would be possible to unlock those fields, referring to the steps described in the document Unlock a locked Jira Software custom field.