updated pytest command following this PR in the pytest repo: pytest-dev/pytest#7408

Author: genegrady

.github/workflows/grpc.yml

@@ -46,7 +46,7 @@ jobs:
       - name: Install troubleshootiung commands
         run: sudo pip install --ignore-installed six
       - name: Run test suite 
-        run: ddtrace-run pytest src/python/grpcio_tests --continue-on-collection-errors -v
+        run: ddtrace-run pytest --import-mode=importlib src/python/grpcio_tests #--continue-on-collection-errors -v