This feature was too coupled to the old closed captions' pads.
(e.g. the old closed captions feature should be enabled for this
to work properly)
Some things were hardcoded and others didn't make sense from the
user experience perspective.
Reverts #876d8aa.
Partially reverts #802964f, removes changes to make closed captions'
pads compatible with live-transcription but keeps provider settings.
a76de8c458