Opening a saved URL of a PDF completely freezes app.

# Issue details

### Duplicate?
Have you searched the issues of this repository if your issue is already known? yes

### Actual behaviour
Opened random article:

No buttons in app work.

Example URL to reproduce with: https://www.pluralsight.com/content/dam/pluralsight2/landing-pages/offers/flow/pdf/Pluralsight_20Patterns_ebook.pdf

### Expected behaviour
- App should not freeze, I don't expect it to display the PDF. It'd be fine to offer to open it, downloaded, in a native PDF reader, or original link in browser.

# Environment details
- **wallabag app version**: 2.4.3 229
- **wallabag app installation source** (e.g. Gplay, F-Droid, manual): fdroid
- **Android OS version**: 11
- **Android ROM** (e.g. stock, LineageOS, SlimRom,…): Lineage
- **Android hardware**: dumpling, oneplus 5t
- **wallabag server version**: 2.4.3
- **Do you have Two-Factor-Authentication enabled?**: probably not

# Logs
## wallabag server
Please paste relevant wallabag server logs here (from file `/var/logs/prod.log`): unavailable

## Web server
Please paste relevant web server logs (e.g. from nginx, Apache, …) here: unavailanle

**NOTE:** Be super sure to remove sensitive data like passwords, note that everybody can look here!

# Your experience with wallabag Android app
Have you had any luck using wallabag Android app before? (Sometimes we get tired of reading bug reports all day and a lil' positive end note does wonders)

It works great, sometimes it pushes notifications of crashes, but I can't see anything braking.