build: remove pre-installed ubuntu user for consistency (#3016)

build/ubuntu/install-packages.sh

@@ -26,8 +26,7 @@ apt-get install -y \
   zstd \
   lbzip2 \
   nfs-common \
-  libpcap0.8 \
-  webp
+  libpcap0.8
 
 # Install Git LFS
 curl -s https://packagecloud.io/install/repositories/github/git-lfs/script.deb.sh | sudo bash

build/ubuntu/setup-user.sh

@@ -2,5 +2,9 @@
 
 set -e
 
+if id ubuntu > /dev/null 2>&1; then
+  deluser ubuntu
+fi
+
 addgroup --gid 1000 minecraft
 adduser --system --shell /bin/false --uid 1000 --ingroup minecraft --home /data minecraft