Move can_view_pipeline_editor to dedicated helper

In order to avoid increasing complexity in the projects_helper,
this change moves can_view_pipeline_editor to its own module.

app/helpers/projects_helper.rb

@@ -784,11 +784,6 @@ module ProjectsHelper
   def project_access_token_available?(project)
     can?(current_user, :admin_resource_access_tokens, project)
   end
-
-  def can_view_pipeline_editor?(project)
-    can_collaborate_with_project?(project) &&
-      ::Gitlab::Ci::Features.ci_pipeline_editor_page_enabled?(project)
-  end
 end
 
 ProjectsHelper.prepend_if_ee('EE::ProjectsHelper')

ee/spec/views/layouts/nav/sidebar/_project.html.haml_spec.rb

@@ -9,7 +9,6 @@ RSpec.describe 'layouts/nav/sidebar/_project' do
     assign(:project, project)
     assign(:repository, project.repository)
     allow(view).to receive(:current_ref).and_return('master')
-    allow(view).to receive(:can_collaborate_with_project?).and_return(true)
   end
 
   describe 'issue boards' do

spec/views/layouts/nav/sidebar/_project.html.haml_spec.rb

@@ -11,7 +11,6 @@ RSpec.describe 'layouts/nav/sidebar/_project' do
     allow(view).to receive(:current_ref).and_return('master')
 
     allow(view).to receive(:can?).and_return(true)
-    allow(view).to receive(:can_collaborate_with_project?).and_return(true)
   end
 
   it_behaves_like 'has nav sidebar'