Multiple datastores for the same file

[trema96]

For android key storage we need to reuse datastores for the application instance otherwise we get the error:

There are multiple DataStores active for the same file: /data/user/0/com.icure.cardinal_sdk_example/files/datastore/cardinal_sdk_storage.preferences_pb. You should either maintain your DataStore as a singleton or confirm that there is no two DataStore's active on the same file (by confirming that the scope is cancelled).