Remove unnecessary shared_examples block

This commit removes an unnecessary shared_examples block that was only
used in one place.

spec/features/projects/releases/user_views_releases_spec.rb

@@ -19,7 +19,6 @@ RSpec.describe 'User views releases', :js do
     project.add_guest(guest)
   end
 
-  shared_examples 'releases page' do
   context('when the user is a maintainer') do
     before do
       sign_in(maintainer)
@@ -145,7 +144,4 @@ RSpec.describe 'User views releases', :js do
       end
     end
   end
-  end
-
-  it_behaves_like 'releases page'
 end