post
https://example.com/public-api/v1/phone_call_legs//audio/uploads
Mint a presigned URL for (re-)uploading a call's audio recording.
Returns {"user_uploads": {"url": ...}}. Upload the audio file directly
to that URL. The phone_call_leg_id is validated as a UUID at request validation (422),
and file_extension is constrained to mp3 by the request schema.
Returns 404 for an unknown id and 409 when the call cannot be
re-uploaded.