Mobile view - Too much empty space

[pcenov]

Observed behavior

See the attached screenshot. Tested in real devices as well as using Chrome's dev tools emulator.

Steps to reproduce the issue

1. Install the following build: https://buildkite.com/learningequality/kolibri-python-package/builds/5658 from https://github.com/learningequality/kolibri/pull/9222
2. Go to the Library > Browse channel

Screenshots

Usage Details

Windows 10 and Ubuntu 20 - Chrome, Firefox