chore: remove emscripten xtask & workflow

.github/workflows/emscripten.yml

@@ -1,30 +0,0 @@
-name: Update Emscripten
-
-on:
-  pull_request:
-    types: [opened, synchronize]
-
-permissions:
-  contents: write
-  pull-requests: read
-
-jobs:
-  update-emscripten:
-    if: github.actor == 'dependabot[bot]'
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v5
-        with:
-          ref: ${{ github.event.pull_request.head.sha }}
-
-      - name: Set up stable Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@v1
-
-      - name: Run emscripten update xtask
-        run: |
-          git config --global user.name "dependabot[bot]"
-          git config --global user.email "49699333+dependabot[bot]@users.noreply.github.com"
-          cargo xtask upgrade-emscripten
-
-      - name: Push updated version
-        run: git push origin HEAD:$GITHUB_HEAD_REF