Don't trip debug asserts when the selector of a CKComponentAction is NULL
Don't trip debug asserts when the selector of a CKComponentAction is NULL

Running the action is a no-op, so checking the validity of it should be too.

dshahidehpour/componentkit,avnerbarr/componentkit,avnerbarr/componentkit,eczarny/componentkit,dshahidehpour/componentkit,eczarny/componentkit,avnerbarr/componentkit,avnerbarr/componentkit,dshahidehpour/componentkit,eczarny/componentkit