changes-notifications blobs are out of sync with production-definition blobs

### Description

The [current script](https://github.com/clearlydefined/operations/tree/main/tools/blobstorage-backupdata) that drives the publication of `changes-notifications` uses the database to find recent changes and gather the definition for each changed coordinate. Some DB definitions are out of sync with the `production-definition` blobs which are the source of truth. This has led to some of the `changes-notifications` definitions to also be out of sync.

### Fix going forward

As the `production-definition` blobs are the source of truth, the script will be updated to use these blob store definitions as the source for definitions recorded in the changes-notifications blob store. It will continue to use the database as the means for identifying changed coordinates.

### Backfilling

The script that will resync the DB definitions with the `production-definition` blobs can resync the `changes-notifications` blobs at the same time. See https://github.com/clearlydefined/service/issues/1142 for more information on this work.

### Related Work

* https://github.com/clearlydefined/service/issues/1142
* https://github.com/clearlydefined/service/issues/958