apps: Use AdwStatusPage when showing "No Apps Found"
The scrolling bug described in [1] and [2] doesn't happen anymore. Apparently this was fixed in [3], which stopped wrapping the status page inside a GtkListBox.
Use AdwStatusPage again, since it makes the code simpler.
- [1] 1ae2c529
- [2] !989 (comment 1837249)
- [3] e2b48962
Edited by Automeris naranja