Remove unused os imports identified by ruff

Signed-off-by: Xing Liu <xingliu14@gmail.com>

Author: xingliu14

tpu_inference/core/disagg_utils.py

@@ -1,6 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 
-import os
 from typing import Tuple
 
 from tpu_inference import envs

tpu_inference/distributed/tpu_connector.py

@@ -60,7 +60,6 @@
 
 import copy
 import functools
-import os
 import threading
 import time
 from concurrent.futures import Future, ThreadPoolExecutor

tpu_inference/platforms/tpu_platform.py

@@ -1,6 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 
-import os
 from typing import TYPE_CHECKING, Optional, Tuple, Union, cast
 
 import jax.numpy as jnp