build: fix cross-spawn location (#5784)

Author: meltsufin

packages/owl-bot/Dockerfile.backend

@@ -25,7 +25,7 @@ RUN apt-get update && \
     rm -rf /var/lib/apt/lists/*
 
 # Remove unnecessary cross-spawn from npm to resolve CVE-2024-21538
-RUN rm -rf /usr/local/lib/node_modules/npm/node_modules/cross-spawn/
+RUN rm -rf /usr/lib/node_modules/npm/node_modules/cross-spawn/
 
 # Stage 1: Build
 FROM NODE_BASE AS BUILD