[Feature Request]: Select default audio track/language

### Guidelines

- [X] I have searched the issue tracker for [open](https://github.com/FreeTubeApp/FreeTube/issues?q=is%3Aopen+is%3Aissue) and [closed](https://github.com/FreeTubeApp/FreeTube/issues?q=is%3Aissue+is%3Aclosed) issues that are similar to the feature request I want to file, without success.
- [X] I have searched the [documentation](https://docs.freetubeapp.io/) for information that matches the description of the feature request I want to file, without success.
- [X] This issue contains only one feature request.

### Problem Description

While FreeTube does support multiple audio tracks nowadays for videos that have them, currently it defaults to the original language of the video. So if I prefer watching foreign videos in another language, e.g. watching English videos dubbed in Spanish, then I have to manually select the Spanish audio for each video I wanna watch.

### Proposed Solution

Add an option, under either "General Settings" or "Player Settings", to select the default audio track for all videos (a specific language, or just the original video's language).

### Alternatives Considered

Another option could be to use the existing "Locale Preference" setting to select the default audio track instead of adding a new setting, though that might be less "flexible" for the end user.

### Issue Labels

ease of use improvement, improvement to existing feature

### Additional Information

_No response_