ci: Remove not triggered manifest_sync workflow

.github/workflows/manifest_sync.yml

@@ -1,51 +0,0 @@
-name: Manifest Synchronization
-
-permissions:
-  contents: read
-
-on:
-  release:
-    types: [published]
-
-env:
-  WORKSPACE: /tmp/workspace
-
-defaults:
-  run:
-    shell: bash --noprofile --norc -CeEuxo pipefail {0}
-
-jobs:
-  sync:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          persist-credentials: true
-
-      - name: Checkout manifest-schema branch
-        run: ./tools/ci/checkout-manifest-schema-branch.sh "${WORKSPACE}"
-
-      - name: Copy over schema
-        run: cp -- ./manifests/* "${WORKSPACE}"
-
-      - name: Stage changes
-        working-directory: ${{ env.WORKSPACE }}
-        run: git add .
-
-      - name: Show diff
-        working-directory: ${{ env.WORKSPACE }}
-        run: git diff HEAD
-
-      - name: Detect changes
-        id: changes
-        working-directory: ${{ env.WORKSPACE }}
-        run: |
-          # This output boolean tells us if the dependencies have actually changed
-          printf "count=%s\n" "$(git status --porcelain=v1 | wc -l)" >>"${GITHUB_OUTPUT}"
-
-      - name: Commit and push
-        # Only push if changes exist
-        if: steps.changes.outputs.count > 0
-        working-directory: ${{ env.WORKSPACE }}
-        run: |
-          git commit -m "Update manifest schema" && git push origin HEAD