Use preinstalled winget on Windows runners

Remove Cyberboss/install-winget action and rely on winget provided by
windows-2025 images; add comment to the ffmpeg install step noting this
assumption

Author: kingwingfly

.github/workflows/release.yaml

@@ -68,14 +68,9 @@ jobs:
           PATH="/tmp/bin:$PATH" make
           make install
           echo "FFMPEG_PKG_CONFIG_PATH=/tmp/ffmpeg/lib/pkgconfig" >> $GITHUB_ENV
-      - name: Install winget
-        if: ${{ matrix.os == 'windows-latest' }}
-        uses: Cyberboss/install-winget@v1
-        with:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-          wget_release_id: latest
       - name: install ffmpeg windows
         if: ${{ matrix.os == 'windows-latest' }}
+        # winget is preinstalled since windows-2025
         run: |
           mkdir ffmpeg
           winget install --id BtbN.FFmpeg.GPL.Shared.8.0 -l ffmpeg --accept-package-agreements --accept-source-agreements