I think you have noticed that at the bottom of that email there is a statement saying:
This message from Microsoft is an important part of a program, service, or product that you or your company purchased or participates in. Microsoft respects your privacy. Please read our Privacy Statement.
And it seems there is no way to unsubscribe it within the Email.
Thank you for response. Unfortunatly this is not an option given that when we share an app the invitation the user receives is from Powerappsfirstname.lastname@example.org. I will create a ticket then to see if we can request this message not to be sent.