Remove async from sparse_embedding_model_name property

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Prevents:

```
ValueError: Unsupported embedding model: <coroutine object AsyncQdrantFastembedMixin.sparse_embedding_model_name at 0x7f7f0e863d00>. Supported models: {'prithvida/Splade_PP_en_v1': {'model': 'prithvida/Splade_PP_en_v1', 'vocab_size': 30522, 'description': 'Misspelled version of the model. Retained for backward compatibility. Independent Implementation of SPLADE++ Model for English', 'size_in_GB': 0.532, 'sources': {'hf': 'Qdrant/SPLADE_PP_en_v1'}}, 'prithivida/Splade_PP_en_v1': {'model': 'prithivida/Splade_PP_en_v1', 'vocab_size': 30522, 'description': 'Independent Implementation of SPLADE++ Model for English', 'size_in_GB': 0.532, 'sources': {'hf': 'Qdrant/SPLADE_PP_en_v1'}}}
```

qdrant_client/async_qdrant_fastembed.py

@@ -66,7 +66,7 @@ def embedding_model_name(self) -> str:
         return self._embedding_model_name
 
     @property
-    async def sparse_embedding_model_name(self) -> Optional[str]:
+    def sparse_embedding_model_name(self) -> Optional[str]:
         return self._sparse_embedding_model_name
 
     def set_model(