fix: move BDI core agent to make documentation generation better

Previously, the BDI Core Agent wasn't included in the docs.

ref: N25B-299

src/control_backend/agents/bdi/__init__.py

@@ -1,4 +1,5 @@
-from .bdi_core_agent.bdi_core_agent import BDICoreAgent as BDICoreAgent
+from control_backend.agents.bdi.bdi_core_agent import BDICoreAgent as BDICoreAgent
+
 from .belief_collector_agent import (
     BDIBeliefCollectorAgent as BDIBeliefCollectorAgent,
 )