release-image: Ignore $DOCKER_USER on restart

Closes #2267

ci/release-image/entrypoint.sh

@@ -5,7 +5,7 @@ set -eu
 # Otherwise the current container UID may not exist in the passwd database.
 eval "$(fixuid -q)"
 
-if [ "${DOCKER_USER-}" ]; then
+if [ "${DOCKER_USER-}" != "${USER-}" ]; then
   echo "$DOCKER_USER ALL=(ALL) NOPASSWD:ALL" | sudo tee -a /etc/sudoers.d/nopasswd > /dev/null
   # Unfortunately we cannot change $HOME as we cannot move any bind mounts
   # nor can we bind mount $HOME into a new home as that requires a privileged container.