feat(dockerfiles): remove ubuntu user from 24.04 docker image

* Removed `ARG PUID` and `ARG PGID` from Dockerfiles for Ubuntu 20.04, 22.04, and 24.04.
* Added a step to remove the default `ubuntu` user in Dockerfile for Ubuntu 24.04.

Dockerfile.ubuntu-2004

@@ -1,8 +1,6 @@
 FROM ubuntu:20.04
 
 ARG DEBIAN_FRONTEND=noninteractive
-ARG PUID=1000
-ARG PGID=1000
 ARG BUILD_DATE
 ARG VCS_REF
 

Dockerfile.ubuntu-2204

@@ -1,8 +1,6 @@
 FROM ubuntu:22.04
 
 ARG DEBIAN_FRONTEND=noninteractive
-ARG PUID=1000
-ARG PGID=1000
 ARG BUILD_DATE
 ARG VCS_REF
 

Dockerfile.ubuntu-2404

@@ -1,8 +1,9 @@
 FROM ubuntu:24.04
 
+## Remove ubuntu user added in 24.04 by default
+RUN touch /var/mail/ubuntu && chown ubuntu /var/mail/ubuntu && userdel -r ubuntu
+
 ARG DEBIAN_FRONTEND=noninteractive
-ARG PUID=1000
-ARG PGID=1000
 ARG BUILD_DATE
 ARG VCS_REF