fix: use UID 1000 for besu user (#6358)

The openjdk-latest Docker image is using UID 1001 for besu, because its
base image ubuntu:23.10 now contains a default "ubuntu" user with UID
1000. (This UID change causes the besu user with UID 1001 to not have
access to files created for past versions with UID 1000.)

We now remove the default ubuntu user and explicitly use UID 1000 when
creating the besu user.

Signed-off-by: Hal Blackburn <hwtb2@cam.ac.uk>

docker/openjdk-latest/Dockerfile

@@ -6,7 +6,10 @@ RUN apt-get update && \
  apt-get install --no-install-recommends -q --assume-yes openjdk-21-jre-headless=21* libjemalloc-dev=5.* adduser=3* && \
  apt-get clean  && \
  rm -rf /var/lib/apt/lists/*  && \
- adduser --disabled-password --gecos "" --home /opt/besu besu && \
+ # Ubuntu 23.10 comes with an "ubuntu" user with uid 1000. We 1000 for besu.
+ userdel ubuntu 2>/dev/null || true && rm -rf /home/ubuntu && \
+ # Ensure we use a stable UID for besu, as file permissions are tied to UIDs.
+ adduser --uid 1000 --disabled-password --gecos "" --home /opt/besu besu && \
     chown besu:besu /opt/besu && \
     chmod 0755 /opt/besu