[ray] allow for specifying ray.init kwargs (i.e. runtime_env) (#7647)

* ray init kwargs

* Update trainer_utils.py

* fix ray args

---------

Co-authored-by: hoshi-hiyouga <hiyouga@buaa.edu.cn>

src/llamafactory/hparams/training_args.py

@@ -46,6 +46,10 @@ class RayArguments:
         default="PACK",
         metadata={"help": "The placement strategy for Ray training. Default is PACK."},
     )
+    ray_init_kwargs: Optional[dict] = field(
+        default=None,
+        metadata={"help": "The arguments to pass to ray.init for Ray training. Default is None."},
+    )
 
     def __post_init__(self):
         self.use_ray = use_ray()