Fixed gitlab_*_variable when using purge (#7251)
* Fixed gitlab_*_variable when using purge, see issue #7250
* Update changelogs/fragments/7251-gitlab-variables-deleteing-all-variables.yml
Co-authored-by: Felix Fontein <felix@fontein.de>
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Co-authored-by: Felix Fontein <felix@fontein.de>
(cherry picked from commit fc2e6c4b45)
Co-authored-by: MaxBidlingmaier <103562872+MaxBidlingmaier@users.noreply.github.com>