fix: update one last ref

Signed-off-by: Samantha Coyle <sam@diagrid.io>

Author: sicoyle

ext/dapr-ext-workflow/dapr/ext/workflow/_durabletask/worker.py

@@ -953,7 +953,7 @@ def _execute_activity(
         stub: stubs.TaskHubSidecarServiceStub,
         completionToken,
     ):
-        instance_id = req.orchestrationInstance.instanceId
+        instance_id = req.workflowInstance.instanceId
 
         if otel_tracer is not None:
             span_context = otel_tracer.start_as_current_span(