ci: Only run build-test-publish-wheel workflow if env var set (#1047)

Signed-off-by: Charlie Truong <chtruong@nvidia.com>

Author: chtruong814

.github/workflows/build-test-publish-wheel.yml

@@ -27,6 +27,7 @@ defaults:
 jobs:
   build-test-publish-wheel:
     uses: NVIDIA-NeMo/FW-CI-templates/.github/workflows/_build_test_publish_wheel.yml@v0.33.0
+    if: ${{ vars.BUILD_TEST_PUBLISH_WHEEL == 'true' }}
     with:
       dry-run: true
       python-package: nemo_rl