ability for admin to use cart addon on backed

if an admin has to manually add multiple services for a client he is unable to do so in a single booking because the cart addon works on the front end only. if we are being pragmatic that cart add on option should be available for the admin on the backend too for this scenario.
If admin book for the client from the front end later down the road there will be no difference if admin booked an appointment or client did on the backend.