storage location not respected on course import

When a course with video transcripts is imported, the path location is not respected; it goes in the root of the storage. Everything else (eg. reading transcripts) appears to correctly respect the location.

For example, if I have the following config (tutor default + tutor-contrib-s3):

MEDIA_ROOT = "/openedx/media/"
VIDEO_TRANSCRIPTS_SETTINGS["STORAGE_KWARGS"]["location"] = MEDIA_ROOT
STORAGES['default']['BACKEND'] = "storages.backends.s3boto3.S3Boto3Storage"
VIDEO_TRANSCRIPTS_SETTINGS["STORAGE_KWARGS"]["location"] = VIDEO_TRANSCRIPTS_SETTINGS["STORAGE_KWARGS"]["location"].lstrip("/")

And I import a course with transcripts, the transcripts will be saved to video-transcripts/ in s3, but it will try reading the transcripts from openedx/media/video-transcripts.

I believe I've been able to reproduce similar behaviour with the new STORAGES based setting, although I think maybe the transcript file didn't get uploaded at all. Perhaps more testing is required there:

STORAGES["video_transcripts"] = {
      "BACKEND": "storages.backends.s3boto3.S3Boto3Storage",
      "OPTIONS": {
          "bucket_name": "{{ S3_STORAGE_BUCKET }}",
          "location": "",
      },
}

This is on Verawood.

Start at the course import path that handles video transcripts and trace how VIDEO_TRANSCRIPTS_SETTINGS and the video_transcripts STORAGES configuration determine upload and read locations. Reproduce the issue with the provided S3 configurations; done means imported transcripts are uploaded under the configured location and can be read from that same location.