Show Add-in on the email surface
Add-in only show on the email surface at the time of install through the App Store inside of Outlook Web, or using the Customise Actions pane in Outlook.
We want to show on the email surface without installing through the App Store, or using the Customise Actions pane. And also we want this when some administrator install the add-in for overall of its tenant.
This is important because Outlook for web users are difficult to find the add-in.