Absence app shows even when not enabled for user? #18

How to use GitHub

• Please use the 👍 reaction to show that you are affected by the same issue.
• Please don't comment if you have no relevant information to add. It's just extra noise for everyone subscribed to this issue.
• Subscribe to receive notifications on status change and new comments.

Steps to reproduce

1. Enable app for only some users
2. As a user that has no access go to settings/user/availability
3. See settings for public holidays

Expected behaviour

You see no trace of the app

Actual behaviour

See settings for public holidays and changing them yields a 500 Error