Disable 'outdated' profiles on checkout submit

It goes like this: Given

• Your default profile/address (which is preselected) has been used in a completed order;
• You spot an error (e.g. your phone number needs an update) and fix it right there by typing in the text boxes on the checkout page;
• ..and click the "continue" button

Your profile gets duplicated (Commerce Order does that, to preserve data on existing orders). But unlike the edit screens in the 'address book', the outdated profile does not get disabled. So now you have two very similar choices in your address book.

Patch fixes that by disabling the outdated profile.

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I just realized there is a small UX issue here, for people who don't pay much attention to the "Addresses on File" select element and don't know that there is a concept of an address book. (In other words: they don't see the difference between 'adding a new address' and 'editing the current address', on this checkout page.)

If they just start typing in a completely new address to send a new order to, may not realize that they are essentially removing the existing address from their address book.

But it's either that, or (as it is now): every time they order something and see an outdated phone number in the default selected address, they correct it again... and the address book starts growing with one duplicate address, two, three, four...

(The patch is on the current version; the text file is the same patch re-rolled on top of #2070643-5: Default address not always used in checkout pane).