FiltersHelperOverrides has been excluded from reloading as it kept a list of role filter search overrides (http://projects.theforeman.org/projects/foreman/wiki/How_to_Create_a_Plugin#Specifying-alternate-auto-complete-path-for-Role-Filters) in a class-level variable.

This can be refactored (like #19464) to make it safe for reloading and move it into the regular services directory instead of registries. As a side effect, this will also make it more testable and less likely to leak behaviour changes between tests.