Regression in #839 due to how NSFetchedResultsController was refactored.
Duplicated entities were not excluded from mapping.
Could "crash" the app with these easy steps:
- Pick a profile
- Unshare the profile on iOS
- Unshare the profile on macOS
- Re-share the profile on iCloud on both iOS and macOS
- Save the profile simultaneously on iOS/macOS
- Assertion failure due to duplicates in
ProfileManager.reloadRemoteProfiles() → "Remote repository must not have
duplicates"