fix(async,ci): skip secret-dependent tests

Add ignores for tests requiring OpenAI secrets.

Author: BloggerBust

.github/workflows/test_core.yml

@@ -99,4 +99,5 @@ jobs:
           --ignore=tests/test_core/test_tracing/test_dataset_iterator.py            \
           --ignore=tests/test_core/test_synthesizer/test_context_generator.py       \
           --ignore=tests/test_core/test_synthesizer/test_conversation_simulator.py  \
-          --ignore=tests/test_core/test_synthesizer/test_generate_from_goldens.py
+          --ignore=tests/test_core/test_synthesizer/test_generate_from_goldens.py   \
+          --ignore=tests/test_core/test_synthesizer/test_synthesizer.py