Issue hyperlink doesn't show in text mode email notification for Thunderbird

Summary

There is no hyperlink for issue URL for text mode email notification in Thunderbird

Steps to Reproduce

• Setup your email account in Thunderbird
• Set the Default outgoing email format to text
• Subscribe/add yourself in the notification scheme

Expected Results

Notification email should show issues hyperlink as below

Actual Results

There is no hyperlink in the issues URL

Workaround

No workaround