iPhone 13 Pro Max ProMotion Support

[Charles David Mupende]

Describe the bug
The app does not support ProMotion and it's higher refresh rates which makes the UI feel sluggish for newer devices.

To Reproduce
Steps to reproduce the behavior:

1. Use a device with ProMotion support e.g. iPhone 13 Pro Max
2. Open the Paperless App
3. Scroll through the UI
4. Notice low refresh rate

Expected behavior
The display should use higher refresh rates while scrolling and automatically scale down the refresh rate when reading.

Additional information
Do you use Paperless NG as a backend: Yes

[Johann Bauer]

Apparently this has only been implemented in Flutter recently: flutter/flutter#90675 (comment)

This should be easy enough to do.