Fix conda-build command availability in CI workflow

Co-authored-by: medley56 <7018964+medley56@users.noreply.github.com>

Author: Copilot

.github/workflows/_build.yml

@@ -79,7 +79,7 @@ jobs:
         shell: bash -l {0}
         run: |
           python --version
-          conda install -y conda-build
+          conda install -n base -y conda-build
           conda build .
           conda build --output .