[diffusion] fix: Fix profiler trace missing Python stack in diffusion pipeline (#14499)

python/sglang/multimodal_gen/runtime/pipelines_core/stages/denoising.py

@@ -599,9 +599,7 @@ class DenoisingStage(PipelineStage):
                 active=batch.num_profiled_timesteps,
                 repeat=5,
             ),
-            on_trace_ready=lambda _: torch.profiler.tensorboard_trace_handler(
-                f"./logs"
-            ),
+            on_trace_ready=None,
             record_shapes=True,
             with_stack=True,
         )