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

test/unit/agents/bdi/test_belief_collector.py

@@ -86,7 +86,7 @@ async def test_send_beliefs_to_bdi(agent):
     sent: InternalMessage = agent.send.call_args.args[0]
     assert sent.to == settings.agent_settings.bdi_core_name
     assert sent.thread == "beliefs"
-    assert json.loads(sent.body)["beliefs"] == [belief.model_dump() for belief in beliefs]
+    assert json.loads(sent.body)["create"] == [belief.model_dump() for belief in beliefs]
 
 
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