Add more user friendly message when a license is revoked

In case a license reservation is revoked from a client application (i.e. by running qtlicensetool -c), the daemon disconnects the client socket and the client application will generate a user visible message that the socket connection was closed by remote side.

This is not very user friendly, as it does not indicate anything about the root cause that the license was revoked. Consider adjusting the message in this context, or handling the license revocation differently.

One potential option is to just revoke the license without triggering socket disconnection. This way the client may implicitly request a new reservation in its next heartbeat socket request.