ci: Use commit-message-validator

Run <https://gitlab.wikimedia.org/repos/ci-tools/commit-message-validator>
locally and under GitLab CI using pre-commit.

Bug: T357182
Bug: T357183

# Please enter the commit message for your changes. Lines starting
# with '#' will be ignored, and an empty message aborts the commit.
#
# Date:      Fri Feb 9 15:36:56 2024 -0700
#
# On branch work/bd808/ci
# Changes to be committed:
#⠀⠀new file:   .gitlab-ci.yml
#⠀⠀new file:   .pre-commit-config.yaml
