ci: Create artifacts of meson logs in dist job

Tests sometimes fail there, but without logs it's hard to know why.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/3754>

.gitlab-ci.yml

@@ -648,6 +648,12 @@ dist-mutter:
         ./src/tests/meta-dbus-runner.py
           --launch=wireplumber
           meson dist -C build
+  artifacts:
+    expire_in: 7 day
+    name: "mutter-${CI_JOB_NAME}-${CI_COMMIT_REF_NAME}"
+    when: always
+    paths:
+      - build/meson-private/dist-build/meson-logs
   rules:
     - if: '$CI_PIPELINE_SOURCE != "merge_request_event"'
       when: manual