Remove unused sdk-index-url context.

.github/workflows/build.yml

@@ -27,7 +27,6 @@ jobs:
         id: build-app
         with:
           sdk-channel: ${{ matrix.sdk-channel }}
-          sdk-index-url: ${{ matrix.sdk-index-url }}
       - name: Upload app artifacts
         uses: actions/upload-artifact@v3
         with: