[Feature] Add search bar to Subtitles selection dialog

[znarfm]

Describe the feature
When downloading videos that contain a large number of auto-generated subtitles like YouTube videos. It is difficult and time-consuming to scroll through the list to find a specific language like en since it would be in the middle of the list.

It would be great if there would be a search functionality for this, similar to how we can search in the app's Preferences modal.

Thanks!