pulse mgmt rest client does not properly return or throw an error when a directory is passed to LoadPlugin

[geauxvirtual]

pulse mgmt rest client does not properly return or throw an error when a directory is passed to LoadedPlugin. This can be seen in the pulsectl client as it will hang when a directory is passed to pulsectl plugin load. In pulsed, an api request is seen to load the plugin, and an API response of 500 is thrown after pulsectl is ^c.