[CI] Add pytest markers in config files. (#719)

Signed-off-by: Alicia <115451386+congw729@users.noreply.github.com>

tools/pre_commit/check_pickle_imports.py

@@ -18,6 +18,7 @@ import regex as re
 ALLOWED_FILES = {
     "vllm_omni/entrypoints/omni_llm.py",
     "tests/e2e/offline_inference/utils.py",
+    "tests/utils.py",
     "vllm_omni/diffusion/distributed/group_coordinator.py",
     "tests/diffusion/attention/test_sequence_parallel.py",
 }