Allow Jira "Send email" feature to use custom domains

Summary

Allow Jira Send email feature to use custom domains

Steps to Reproduce

1. Setup a custom email address & configure Jira Cloud to send emails on behalf of your domain
2. Go to Settings > System > Send email (under Mail)

Expected Results

Able to change the From to a custom domain email address 

Actual Results

From can only be jira@domain.atlassian.net 

Workaround

Currently there is no known workaround for this behavior. A workaround will be added here when available