Improve legibility of Gitlab CI (#33482)

Use --backtrace in ci instead of --debug to reduce verbosity
and don't show log on error, since log is already printed

share/spack/gitlab/cloud_pipelines/stacks/tutorial/spack.yaml

@@ -71,7 +71,7 @@ spack:
       - spack config add "config:install_tree:projections:${SPACK_JOB_SPEC_PKG_NAME}:'morepadding/{architecture}/{compiler.name}-{compiler.version}/{name}-{version}-{hash}'"
       - if [[ -r /mnt/key/intermediate_ci_signing_key.gpg ]]; then spack gpg trust /mnt/key/intermediate_ci_signing_key.gpg; fi
       - if [[ -r /mnt/key/spack_public_key.gpg ]]; then spack gpg trust /mnt/key/spack_public_key.gpg; fi
-      - spack -d ci rebuild
+      - spack --color=always --backtrace ci rebuild
 
     image: { "name": "ghcr.io/spack/tutorial-ubuntu-18.04:v2021-11-02", "entrypoint": [""] }
     match_behavior: first