As a Plus subscriber Artist Only Mode is available on my Android Phone but it's missing on the Sony TV Android Pandora App. All other modes are visible. Doesn't matter which artist or station. Not visible anywhere
Licensing regulations require a Pandora Premium subscription in order to be able to listen to your station in "Artist Only" mode.
Free listeners and Pandora Plus subscribers will be able to view an advertisement to activate a Premium Access session in order to listen. These sessions can only be enabled on a mobile device or the web. That's why you wouldn't see the option on your TV. However, once you've started the session, it should transfer to your other devices, like your TV, and Artist Only Mode should appear then.