skip tracing tests if token unavailable (#1493)

SUMMARY:
some tests in `tests/llmcompressor/transformers/tracing/test_models.py`
requiring access to gated HF hub models will fail for community user
PRs, because `HF_TOKEN` is not injected. This just skips the tests in
question.

This update allows #1446 and #1445 to pass GHA checks so that they can
be merged in


TEST PLAN:
n/a

Signed-off-by: Brian Dellabetta <bdellabe@redhat.com>

Author: brian-dellabetta

tests/llmcompressor/transformers/tracing/test_models.py

@@ -1,3 +1,5 @@
+import os
+
 import pytest
 from transformers import (
     AutoModelForCausalLM,
@@ -16,6 +18,10 @@
 from llmcompressor.utils.pytorch.module import get_no_split_params
 
 
+@pytest.mark.skipif(
+    os.getenv("HF_TOKEN") is None,
+    reason="Skipping tracing tests requiring gated model access",
+)
 @pytest.mark.parametrize(
     "model_id,model_class,targets,modality,backends",
     [