html tags in email text

@Didayolo

we need to test this on test server. I think this change should fix the issue

How to test:

Send an email to a participant with text:

**bold** [link](https://codabench.org)

Participant should receive:

bold link

Participant should not receive:

<strong>bold</strong> <a href="https://codabench.org">link</a>

Why I think this is fixed?

Before the fix, I see the following in the django logs:

<p>&lt;strong&gt;bold&lt;/strong&gt; &lt;a href="https://codabench.org"&gt;link&lt;/a&gt;</p>

after the fix I see this:

<p><strong>bold</strong> <a href="https://codabench.org">link</a></p>

If this fixes the problem, then I will cleanup and add some comments