Fix Atik connection: remove ArtemisDeviceCount() from __init__

Calling ArtemisDeviceCount() at SDK load time breaks the subsequent
ArtemisConnect() call in _check_connection. The SDK requires the
enumeration to happen immediately before Connect() in a single sequence.
The original code never called it in __init__ (there was a NameError
before that line), so this restores the original working behaviour.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>