Use previous available state (#540)

matter_server/server/device_controller.py

@@ -513,7 +513,7 @@ async def interview_node(self, node_id: int) -> None:
             ),
             last_interview=datetime.utcnow(),
             interview_version=DATA_MODEL_SCHEMA_VERSION,
-            available=True,
+            available=existing_info.available if existing_info else False,
             attributes=parse_attributes_from_read_result(read_response.tlvAttributes),
         )