Remove unused code and comments in GPUDiffusionModelRunner for improved clarity

- Deleted the `has_kv_transfer_group` import as it was not utilized.
- Cleaned up commented-out code related to model methods, focusing on the forward method.
- Added a TODO comment to implement the diffuse method for additional model support.

vllm_omni/worker/gpu_diffusion_model_runner.py

@@ -1,5 +1,3 @@
-# SPDX-License-Identifier: Apache-2.0
-
 from __future__ import annotations
 
 from typing import Optional, Union, List
@@ -13,7 +11,6 @@ from vllm.v1.worker.gpu_model_runner import (
     EMPTY_MODEL_RUNNER_OUTPUT,
     IntermediateTensors,
     get_pp_group,
-    has_kv_transfer_group,
     set_forward_context,
 )
 from vllm.v1.worker.utils import sanity_check_mm_encoder_outputs
@@ -187,21 +184,13 @@ class GPUDiffusionModelRunner(OmniGPUModelRunner):
         # For Qwen 2.5 Omni's current implementation, we only support the forward method
         if hasattr(self.model, "forward"):
             return self.model.forward(**kwargs)
-        
-        # if hasattr(self.model, "sample"):
-        #     return self.model.sample(**kwargs)
-        # if hasattr(self.model, "forward"):
-        #     return self.model.forward(**kwargs)
-        # if hasattr(self.model, "diffuse"):
-        #     return self.model.diffuse(**kwargs)
+        #TODO: add the diffuse method for other models
 
         raise RuntimeError(
             "The loaded model does not expose diffusion interfaces 'sample', "
             "'forward', or 'diffuse'. Please implement one of them or adapt the runner.")
 
 
-
-
     @torch.inference_mode()
     def _dummy_run(
         self,