Fixes #7394: Stop blocking plugin routes from being loaded properly.

Prior to tis change, if a Foreman plugin was declared via bundler
after Katello in load order, the routes would not get properly loaded
within the application. This meant that these routes were in-accessible,
and could lead to intermittent and un-expected behaviors.
Merge pull request #4648 from ehelms/fixes-7394

Fixes #7394: Stop blocking plugin routes from being loaded properly.