chore: simplify code more

Author: zastrowm

src/strands/event_loop/event_loop.py

@@ -154,18 +154,12 @@ async def event_loop_cycle(
                 model_events = _handle_model_execution(
                     agent, cycle_span, cycle_trace, invocation_state, tracer, structured_output_context
                 )
-                try:
-                    async for model_event in model_events:
-                        if not isinstance(model_event, ModelStopReason):
-                            yield model_event
-                finally:
-                    await model_events.aclose()
+                async for model_event in model_events:
+                    if not isinstance(model_event, ModelStopReason):
+                        yield model_event
 
                 stop_reason, message, *_ = model_event["stop"]
                 yield ModelMessageEvent(message=message)
-        except Exception as e:
-            tracer.end_span_with_error(cycle_span, str(e), e)
-            raise
         except BaseException as e:
             tracer.end_span_with_error(cycle_span, str(e), e)
             raise