[v1] add accelerator (#9607)

src/llamafactory/v1/config/sample_args.py

@@ -14,12 +14,8 @@
 
 
 from dataclasses import dataclass, field
-from enum import Enum
 
-
-class SampleBackend(Enum):
-    HF = "hf"
-    VLLM = "vllm"
+from .arg_utils import SampleBackend
 
 
 @dataclass