Fix: 'Sound' named track is not automatically exported
Description of fix
Put back a refactor version of auto sound channel addition into export.
How to test it
Export any timeline with a track called "Sound" or "sound".
Checklist
Please check if your MR fulfills the following requirements:
-
Build was run locally and any changes were pushed -
Lint has passed locally without error -
CHANGELOG.md has been updated -
Branch has been rebased on merge branch
FYI: @alefeve