Remove .gitlab-ci.yml for GLFM verification script

What does this MR do and why?

This is a partial revert of !101118 (merged) to make docs-only pipelines work again.

Erros was: 'glfm-verify' job needs 'setup-test-env' job, but 'setup-test-env' is not in any previous stage when the pipeline runs for a docs MR.

Example pipeline error: https://gitlab.com/gitlab-org/gitlab/-/pipelines/670469244#/

This also fixes a broken FOSS build: https://gitlab.com/gitlab-org/gitlab-foss/-/jobs/3193132979

MR acceptance checklist

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