Vadapav scraper causes mov-cli to crash when returning subtitles.

[lowpolyv2]

It's returning just a string when it's supposed to be returning a list of strings (aka subtitles urls): https://github.com/JDALab/film-central/blob/main/film_central/vadapav/scraper.py#L124-L149

[lowpolyv2]

It crashes in v4.5 of mov-cli as in that version of mov-cli assumes subtitles is either a list of strings or a list of subtitle objects. Making it a list of strings here should solve it for all versions.

@Fraei2 Can you maybe look into this later?