Mention email notification should include Summary in the subject line

Description

Currently, mention email notifications does not work like other Jira notifications both in how the From email is coming from, but also that it does not include the Summary of the ticket in the subject, which can become difficult to identify, analyze, organize and deal with in the mail box.

This request is to make it easier and include the subject in the mention email notification, streamlining all communications from Jira.