Fix profiles factory

The RSpec seed 34224 was failling: ./spec/controllers/profiles_controller_spec.rb:168

You can check with: rspec --exclude-pattern "spec/integration/**/*_spec.rb" --seed 34224

This is because the Profile equality operator checks just for id. Thus independent sequences were leading to equal ids.

Creating a factory inheritance enables to remove duplications and ensure there is a unique sequence generating ids.