ci(desktop): add checkout step before running release tag script

.github/workflows/desktop-release.yml

@@ -130,6 +130,11 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      - uses: actions/checkout@v4
+        with:
+          sparse-checkout: scripts
+          ref: ${{ github.event_name == 'workflow_dispatch' && github.event.inputs.tag || github.ref }}
+
       - name: Resolve release tag
         shell: bash
         run: node scripts/emit-release-env.mjs --source-tag "$SOURCE_TAG" >> "$GITHUB_ENV"