In scrolled mode, going back a page (PageUp) on the cover page gets stuck

Describe the bug If you go back a page using the keyboard shortcut (Page Up) on the cover page, Foliate gets "stuck" on the cover page and no longer allows you to navigate to other pages until you go back to the library and re-open the book.

To Reproduce Steps to reproduce the behavior:

1. Use single-page view on an epub (not sure if required, but this is the context where I encountered the bug)
2. Go to the cover page of a book
3. Press the "Page Up" key to go back a page

Expected behavior Pressing "Page Up" on the cover page should do nothing and leave you on the cover page while still being able to navigate the rest of the book properly.

Version:

• Foliate version: 3.3.0
• OS/Distribution and version: Void Linux
• Desktop environment: X11
• Installation method: System package manager