Backport #28942 by @Zettat123
In #28691, schedule plans will be deleted when a repo's actions unit is
disabled. But when the unit is enabled, the schedule plans won't be
created again.
This PR fixes the bug. The schedule plans will be created again when the
actions unit is re-enabled
---------
Co-authored-by: Zettat123 <zettat123@gmail.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Giteabot