test: create tests for belief extractor agent

Includes changes in schemas. Change type of `norms` in `Program` imperceptibly, big changes in schema of `BeliefMessage` to support deleting beliefs.

ref: N25B-380

src/control_backend/agents/bdi/belief_collector_agent.py

@@ -144,7 +144,7 @@ class BDIBeliefCollectorAgent(BaseAgent):
         msg = InternalMessage(
             to=settings.agent_settings.bdi_core_name,
             sender=self.name,
-            body=BeliefMessage(beliefs=beliefs).model_dump_json(),
+            body=BeliefMessage(create=beliefs).model_dump_json(),
             thread="beliefs",
         )