Don't present the user a previous/next item button if there is no previous/next item

Steps to reproduce:
1. Create multiple series
2. Open "Series Details"
3. Navigate to the previous item again and again

Actual Results:
While at some point there is no previous item anymore, the navigation button is still shown and active

Expected Results:
Don't show the navigation button at all if it does not do anything

Workaround (if any):
Simply ignore