[Chapel Merge] Add chpl-tester user to sudo in CI container

Branch: refs/heads/main
Revision: bdfa5e8f8b62c87dbd34eee84d3d3016b83ec73c
Author: jabraham17
Link: Add chpl-tester user to sudo in CI container by jabraham17 · Pull Request #29335 · chapel-lang/chapel · GitHub
Log Message:
Add chpl-tester user to sudo in CI container (#29335)

Adds chpl-tester user to the sudo group for the CI container

Allows a container to run in user-mode and still install extra packages
as needed

[Reviewed by @arifthpe]

Compare: Comparing 072fa31c18f3780b7629135cb31df2a95e50c666...b2ddcfb0f11de894965277bc61c7fad5b73d019d · chapel-lang/chapel · GitHub

Diff:
M util/packaging/docker/github-ci/Dockerfile
https://github.com/chapel-lang/chapel/pull/29335.diff