What is the correct method for getting a client to purchase a Craft license? What is the recommended way from P&amp;T to get a client to purchase a license for Craft CMS? It doesn't actually say how on the website.

If you give a user literally all the permissions Craft has, when they log in to an unlicensed Craft Pro install, they'll see this warning at the top:



If they click Resolve, they get taken to /admin/plugin-store/upgrade-craft and see this error:



The only way I can see for a client to purchase a license is to make them a full Admin, which goes against everything the permissions are set up for. I don't ever want to make a client a full site administrator because they can easily break stuff.

Context: I'm working on behalf of a larger design agency, and the end client is liable for purchasing their own licenses. The design agency is not buying it on their behalf.
I normally pay for the license and bill back to the client, turning off automatic renewal. After purchasing, if the client wants to have access to their license, I have them create a Craft ID account and transfer the license to them.