[memory refactor][5/n] Migrate all vector_io providers (#835)

See https://github.com/meta-llama/llama-stack/issues/827 for the broader
design.

This PR finishes off all the stragglers and migrates everything to the
new naming.

llama_stack/providers/inline/agents/meta_reference/persistence.py

@@ -21,7 +21,7 @@ log = logging.getLogger(__name__)
 class AgentSessionInfo(BaseModel):
     session_id: str
     session_name: str
-    memory_bank_id: Optional[str] = None
+    vector_db_id: Optional[str] = None
     started_at: datetime
 
 
@@ -52,12 +52,12 @@ class AgentPersistence:
 
         return AgentSessionInfo(**json.loads(value))
 
-    async def add_memory_bank_to_session(self, session_id: str, bank_id: str):
+    async def add_vector_db_to_session(self, session_id: str, vector_db_id: str):
         session_info = await self.get_session_info(session_id)
         if session_info is None:
             raise ValueError(f"Session {session_id} not found")
 
-        session_info.memory_bank_id = bank_id
+        session_info.vector_db_id = vector_db_id
         await self.kvstore.set(
             key=f"session:{self.agent_id}:{session_id}",
             value=session_info.model_dump_json(),