Request: CUPS Snap (“cups”) auto connection to of cups:cups-control to cups:admin and also of the network-manager-observe interface

@till.kamppeter I have just adjusted the cups snap declaration to allow connecting to itself via the cups-control slot and made both cups and cups-control slots slots-per-plug: * so apps will be able to connect to both slots simultaneously.

Could you please confirm this is all working as expected?

Thanks!