fix: don't suppress npm install errors for essential omr externals

Dockerfile

@@ -86,8 +86,8 @@ RUN cd backend/omr-service && ONNXRUNTIME_NODE_INSTALL=skip npm install --omit=d
 RUN npm init -y > /dev/null 2>&1 \
     && npm install --no-package-lock \
        js-sha1 math-erf lodash spark-md5 portfinder python-shell \
-       skia-canvas gl msgpackr "yargs@^17" \
-       > /dev/null 2>&1; true
+       msgpackr "yargs@^17" \
+    && npm install --no-package-lock skia-canvas gl 2>/dev/null; true
 
 # --- Copy pre-built frontend ---
 COPY --chown=node dist/ ./dist/