chroma: Avoid repeated acoustid submissions

Currently there is nothing at all preventing you from submitting the same fingerprints more than once, and it is very easy to accidentally do.

The acoustid service also does no duplicate checking, so submitting duplicate fingerprints inflates the count/weight of that submission which is pretty bad.

Tools like musicbrainz picard prevent you from submitting fingerprints multiple times afaik.

The issue names no files, tests, or entry points. Start by locating the AcoustID fingerprint submission path and how prior submissions are tracked; done means accidentally submitting the same fingerprints again is prevented without inflating the service's submission count or weight.

Written by the indexing model from the issue text.