ci: move flatpak back to i686 for now

.github/workflows/c-cpp.yml

@@ -162,7 +162,7 @@ jobs:
     - uses: actions/checkout@v4
     - uses: actions/download-artifact@v4
       with:
-        name: pd-x86_64-linux
+        name: pd-i686-linux
         path: dist/linux/bin/
 
     - uses: flatpak/flatpak-github-actions/flatpak-builder@v6