[NFC] polish colossalai/context/moe_context.py code style (#2693)

colossalai/context/moe_context.py

@@ -1,3 +1,5 @@
+from typing import Tuple
+
 import torch
 import torch.distributed as dist
 
@@ -5,8 +7,6 @@ from colossalai.context.parallel_mode import ParallelMode
 from colossalai.context.singleton_meta import SingletonMeta
 from colossalai.tensor import ProcessGroup
 
-from typing import Tuple
-
 
 def _check_sanity():
     from colossalai.core import global_context as gpc