[Infra] add worker restart and retry flags to local_testing CI jobs

Match the resilience config that the llm_translation job already uses:
--max-worker-restart=5 lets xdist replace workers killed by
pytest-timeout's os._exit(1) instead of failing the whole job, and
--retries 2 --retry-delay 5 self-heals transient network flakes.

Preserves real integration test coverage; no test code changes needed.

.circleci/config.yml

@@ -235,7 +235,10 @@ jobs:
                 -k \"not test_python_38.py and not test_basic_python_version.py and not router and not assistants and not langfuse and not caching and not cache\" \
                 -n 4 \
                 --timeout=300 \
-                --timeout_method=thread"
+                --timeout_method=thread \
+                --retries 2 \
+                --retry-delay 5 \
+                --max-worker-restart=5"
           no_output_timeout: 15m
       - run:
           name: Rename the coverage files
@@ -300,7 +303,10 @@ jobs:
                 -k \"not test_python_38.py and not test_basic_python_version.py and not router and not assistants and not langfuse and not caching and not cache\" \
                 -n 4 \
                 --timeout=300 \
-                --timeout_method=thread"
+                --timeout_method=thread \
+                --retries 2 \
+                --retry-delay 5 \
+                --max-worker-restart=5"
           no_output_timeout: 15m
       - run:
           name: Rename the coverage files