GitLab Runner 16.6.0 causes Systemd to fail in Docker Containers

Summary

GitLab Runner 16.5.0 can be used to start Docker Containers running Systemd, the way I have been doing this is based on this Stack Overflow post which is elaborated on the GitLab Forum, with GitLab Runner 16.6.0 this method fails with:

Explicit --user argument required to run as user manager.

Steps to reproduce

The files in this git repo can be used to build a Docker container that can be run via GitLab CI with GitLab Running <= 16.5.0 with Systemd, this image that is build can be accessed here registry.git.coop/webarch/containers/images/bookworm:20231016, an example .gitlab-ci.yml that uses this image can be found here and and results of the last run (with 16.5.0) can be found here, the results from using 16.6.0 can be found here:

Using docker image sha256:8f1aff751aa0f7ac0f8e60b8234eba8de1461f481448ca9f66c757208b9d864f for registry.git.coop/webarch/containers/images/bookworm:20231119 with digest registry.git.coop/webarch/containers/images/bookworm@sha256:b1eac9cef01c39b372fd5f662c006432da986fe422e70f29634ab92f2c246362 ...
Explicit --user argument required to run as user manager.
Cleaning up project directory and file based variables 00:01
ERROR: Job failed: exit code 1

Environment description

The gitlab-runner.service and /etc/gitlab-runner/config.toml files have been posted to the forum.