Fix: cases with empty sparsity config (vllm-project#12057)

Signed-off-by: Rahul Tuli <[email protected]>

Author: rahul-tuli

vllm/model_executor/layers/quantization/compressed_tensors/compressed_tensors.py

@@ -113,7 +113,7 @@ def _sparsity_scheme_map_from_config(
         :return: A dictionary mapping target layer names to their corresponding
             sparsity compression configurations
         """
-        if (sparsity_config := config.get(SPARSITY_CONFIG_NAME)) is None:
+        if not (sparsity_config := config.get(SPARSITY_CONFIG_NAME)):
             return dict()
 
         sparsity_config = SparsityCompressionConfig.model_validate(