Bump the actions group with 2 updates

Bumps the actions group with 2 updates: [actions/download-artifact](https://github.com/actions/download-artifact) and [prefix-dev/setup-pixi](https://github.com/prefix-dev/setup-pixi).


Updates `actions/download-artifact` from 4 to 5
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](https://github.com/actions/download-artifact/compare/v4...v5)

Updates `prefix-dev/setup-pixi` from 0.8.11 to 0.8.14
- [Release notes](https://github.com/prefix-dev/setup-pixi/releases)
- [Commits](https://github.com/prefix-dev/setup-pixi/compare/v0.8.11...v0.8.14)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '5'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
- dependency-name: prefix-dev/setup-pixi
  dependency-version: 0.8.14
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/build.yml

@@ -142,7 +142,7 @@ jobs:
         with:
           python-version: ${{ matrix.python }}
           allow-prereleases: true
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v5
         with:
           name: notebook-dist-${{ github.run_number }}
           path: ./dist

.github/workflows/playwright-update.yml

@@ -86,7 +86,7 @@ jobs:
       - name: Build
         uses: ./.github/actions/build-dist
 
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v5
         with:
           name: notebook-dist-${{ github.run_number }}
           path: ./dist

.github/workflows/ui-tests.yml

@@ -39,7 +39,7 @@ jobs:
       - name: Base Setup
         uses: jupyterlab/maintainer-tools/.github/actions/base-setup@v1
 
-      - uses: actions/download-artifact@v4
+      - uses: actions/download-artifact@v5
         with:
           name: notebook-dist-${{ github.run_number }}
           path: ./dist

.github/workflows/upgrade-jupyterlab-dependencies.yml

@@ -79,7 +79,7 @@ jobs:
             jlpm
             jlpm deduplicate
           fi
-      - uses: prefix-dev/setup-pixi@v0.8.11
+      - uses: prefix-dev/setup-pixi@v0.8.14
         with:
           pixi-version: v0.41.4
           manifest-path: pyproject.toml