SAC-29767: updated config.yaml

Author: atttiwari

.circleci/config.yml

@@ -42,6 +42,7 @@ jobs:
             uv pip install --upgrade awscli
             aws s3 cp s3://com-stitchdata-dev-deployment-assets/environments/tap-tester/tap_tester_sandbox dev_env.sh
             source dev_env.sh
+            unset USE_STITCH_BACKEND
             run-test --tap=tap-gitlab tests