Fix#30243
We only checking unit disabled when detecting workflows, but not in
runner `FetchTask`.
So if a workflow was detected when action unit is enabled, but disabled
later, `FetchTask` will still return these detected actions.
Global setting: repo.ENABLED and repository.`DISABLED_REPO_UNITS` will
not effect this.
(cherry picked from commit d872ce006c0400edb10a05f7555f9b08070442e3)
84abf4bd91