🔧(dockerfile) remove pip from backend image

pip is not used in production, we can remove it in the production to
avoid having to maintain library linked to it and that can possibly
contains CVEs

Dockerfile

@@ -160,6 +160,9 @@ FROM core AS backend-production
 # Remove apk cache, we don't need it anymore
 RUN rm -rf /var/cache/apk/*
 
+# pip is not needed at runtime (the dependencies are installed with uv)
+RUN /usr/local/bin/python -m pip uninstall --yes pip
+
 ARG IMPRESS_STATIC_ROOT=/data/static
 
 # Gunicorn - not used by default but configuration file is provided