[Bugfix] Fix NameError in OmniDiffusion init for Bagel/NextStep after GLM-Image merge

Signed-off-by: lishunyang12 <lishunyang12@gmail.com>

Author: lishunyang12

vllm_omni/entrypoints/omni_diffusion.py

@@ -86,17 +86,16 @@ def __init__(self, od_config: OmniDiffusionConfig | None = None, **kwargs):
                 od_config.tf_model_config = TransformerConfig()
                 od_config.update_multimodal_support()
             elif model_type == "glm-image" or "GlmImageForConditionalGeneration" in architectures:
-                pipeline_class = "GlmImagePipeline"
+                od_config.model_class_name = "GlmImagePipeline"
+                od_config.tf_model_config = TransformerConfig()
+                od_config.update_multimodal_support()
             elif architectures and len(architectures) == 1:
-                pipeline_class = architectures[0]
-
-            if pipeline_class is None:
+                od_config.model_class_name = architectures[0]
+                od_config.tf_model_config = TransformerConfig()
+                od_config.update_multimodal_support()
+            else:
                 raise ValueError(f"Unknown model type: {model_type}, architectures: {architectures}")
 
-            od_config.model_class_name = pipeline_class
-            od_config.tf_model_config = TransformerConfig()
-            od_config.update_multimodal_support()
-
         self.engine: DiffusionEngine = DiffusionEngine.make_engine(od_config)
 
     def generate(