chore(ci): remove gcs source test (#18763)

ci/workflows/main-cron.yml

@@ -611,29 +611,6 @@ steps:
     timeout_in_minutes: 25
     retry: *auto-retry
 
-  # TODO(Kexiang): Enable this test after we have a GCS_SOURCE_TEST_CONF.
-  # - label: "GCS source on OpenDAL fs engine"
-  #   key: "s3-source-test-for-opendal-fs-engine"
-  #   command: "ci/scripts/s3-source-test-for-opendal-fs-engine.sh -p ci-release -s gcs_source.py"
-  #   if: |
-  #     !(build.pull_request.labels includes "ci/main-cron/run-selected") && build.env("CI_STEPS") == null
-  #     || build.pull_request.labels includes "ci/run-s3-source-tests"
-  #     || build.env("CI_STEPS") =~ /(^|,)s3-source-tests?(,|$$)/
-  #   depends_on: build
-  #   plugins:
-  #     - seek-oss/aws-sm#v2.3.1:
-  #         env:
-  #           S3_SOURCE_TEST_CONF: ci_s3_source_test_aws
-  #     - docker-compose#v5.1.0:
-  #         run: rw-build-env
-  #         config: ci/docker-compose.yml
-  #         mount-buildkite-agent: true
-  #         environment:
-  #           - S3_SOURCE_TEST_CONF
-  #     - ./ci/plugins/upload-failure-logs
-  #   timeout_in_minutes: 20
-  #   retry: *auto-retry
-
   - label: "pulsar source check"
     key: "pulsar-source-tests"
     command: "ci/scripts/pulsar-source-test.sh -p ci-release"