remove concurrency gate from queue step

Author: bmorelli25

.buildkite/build_pipeline.yml

@@ -28,12 +28,11 @@ steps:
   - label: "Check for queue"
     if: build.source == "schedule"
     command: ".buildkite/scripts/check_queue.sh"
-    concurrency: 1
-    concurrency_group: docs-build-${BUILDKITE_BRANCH}
   - wait
   - label: "Full rebuild or incremental build?"
     if: build.source == "schedule"
     command: ".buildkite/scripts/compare_commits.sh"
+    concurrency: 1
     concurrency_group: docs-build-${BUILDKITE_BRANCH}
   - label: ":white_check_mark: Build docs"
     command: |