Is there a way to get all instances of ManagedSettingsStore that my app has previously configured?
I managed to get into a situation, where I removed the identifier in my database, but forgot to clear the store and now the app is shielding couple of apps and I am unable to stop it.
What is the proper workflow for this?
You can unenroll the device from Family Controls in order to revoke any restrictions set using ManagedSettingsStore.
Currently there is no way to query for previously configured ManagedSettingsStore instances, but if you'd like to clear all settings for your process, you can simply revoke authorization for the app and all settings will automatically be cleared from the device.
If this is something you'd like to see in a future iteration of the API, I recommend you file a feature request for ManagedSettings through Feedback Assistant.