store: Destroy Persona Stores after Personas
Each Persona in the list (Contacts.Store.base_model) holds a weak reference to a PersonaStore in Contacts.Store._address_books which must last until each Persona is destroyed. During app teardown, the generated Contacts.Store destructor unreferences each property in the declared order. The Folks.Persona destructor sets its individual property to null, sending a notify signal to the Folks.Individual (_persona_notify_cb then _set_personas), which accesses the Folks.Persona.store weak reference.
Destroy the PersonaStores after the Personas by moving the property down, influencing the default destructor.
This fixes a crash on exit.