Plaintext storage of encrypted fields via skipped embedded models in encryption schema generation

Mongoid may omit encryption rules for fields declared on embedded models when generating the client-side field-level encryption schema. Applications that enable this feature can therefore store values intended to be encrypted in readable form, with no error or warning. A party with routine read access to the database, a backup, or the underlying data files may then see data that was meant to remain unreadable outside the application.