Make sure the layer that adds emscripten doesn't have the huge IDs

Dockerfile-ubuntu2404

     git checkout 3.1.6 && \
     ./emsdk install 3.1.6 && \
     ./emsdk activate 3.1.6 && \
-    sudo cp -prv ./emsdk_env.sh /etc/profile.d/
+    sudo cp -prv ./emsdk_env.sh /etc/profile.d/ && \
+    chown root:root /emsdk -R
 
 # Warmup emscripten (this will pre-fetch SDL2, and cache it)
 RUN /emsdk/upstream/emscripten/em++ -s WASM=1 -s USE_SDL=2 -s USE_SDL_TTF=2 -O3 /dev/null || true