Fix filters in csv exports for Lessons page

[ozer550]

Summary

• Refactor sorting and filtering in COACH->LESSONS page.
• Reflect the filters while downloading the csv files.

Reviewer guidance

• Add some lessons.
• Try filtering combinations with status and recipients.
• Download CSV and see if the filters reflect.

[github-actions]

Build Artifacts

Asset type	Download link
PEX file	kolibri-0.18.0a0.dev0_git.157.gfefdbf01.pex
Windows Installer (EXE)	kolibri-0.18.0a0.dev0+git.157.gfefdbf01-windows-setup-unsigned.exe
Debian Package	kolibri_0.18.0a0.dev0+git.157.gfefdbf01-0ubuntu1_all.deb
Mac Installer (DMG)	kolibri-0.18.0a0.dev0+git.157.gfefdbf01.dmg
Android Package (APK)	kolibri-0.18.0a0.dev0+git.157.gfefdbf01-0.1.4-debug.apk
Raspberry Pi Image	kolibri-pi-image-0.18.0a0.dev0+git.157.gfefdbf01.zip
TAR file	kolibri-0.18.0a0.dev0+git.157.gfefdbf01.tar.gz
WHL file	kolibri-0.18.0a0.dev0+git.157.gfefdbf01-py2.py3-none-any.whl

[pcenov]

Thanks @ozer550 - I confirm that now I am correctly seeing the filtered values when I export the report as CSV.

[marcellamaki]

Thank you @ozer550!