Misleading message "Episode is already published." is displayed on episode dashboard

Describe the bug

After cancelling the publication of a episode, the message "Episode is already published." is displayed

Steps to reproduce

1. Add an episode and save it
2. Open the not published episode
3. Click on [Publish]
4. Click on [Cancel publication]
5. Back on episode dashboard the message "Episode is already published." is shown

Expected behavior

Messsage "Episode is NOT published."

Actual behavior

"Episode is already published." is shown on episode dashboard

• Castopod: 1.0.0-beta.8
• OS: Castopod Hosting
• Browser: Firefox