Making sender name go in-line with message body only if
the html starts with <p> tag since it won't look good
if the message starts with a code snippet, ul, etc.
If message starts with p tag we can safely assume that
it can go in-line with sender name.
Make sure 's, &s, and other characters are not HTML-escaped in subject
lines and plain-text emails.
Hack so that this isn't blocking the release of Zulip 1.6. A more robust way
to do this would be to have two different template Engines, one that renders
HTML, and one that doesn't.
Fixes#5088.
vaibhavrajsingh2001
Vishnu Ks
Puneeth Chaganti
Tim Abbott
Rishi Gupta