Do not consider attributes using the :unless option as required

Remove some of the factories introduced in commit 66334b5 as now we do
not need them anymore.

Co-Authored-By: Javi Martín <35156+javierm@users.noreply.github.com>

spec/models/progress_bar_spec.rb

@@ -3,6 +3,7 @@ require "rails_helper"
 describe ProgressBar do
   let(:progress_bar) { build(:progress_bar) }
 
+  it_behaves_like "globalizable", :progress_bar
   it_behaves_like "globalizable", :secondary_progress_bar
 
   it "is valid" do