Revert unnecessary code running_or_pending_build_count removal

app/models/ci/build.rb

@@ -359,6 +359,7 @@ module Ci
       project.execute_hooks(build_data.dup, :job_hooks)
       project.execute_services(build_data.dup, :job_hooks)
       PagesService.new(build_data).execute
+      project.running_or_pending_build_count(force: true)
     end
 
     def artifacts_metadata_entry(path, **options)

app/models/project.rb

@@ -1494,6 +1494,12 @@ class Project < ActiveRecord::Base
     update_column(:import_jid, nil)
   end
 
+  def running_or_pending_build_count(force: false)
+    Rails.cache.fetch(['projects', id, 'running_or_pending_build_count'], force: force) do
+      builds.running_or_pending.count(:all)
+    end
+  end
+
   # Lazy loading of the `pipeline_status` attribute
   def pipeline_status
     @pipeline_status ||= Gitlab::Cache::Ci::ProjectPipelineStatus.load_for_project(self)

spec/features/projects/jobs/user_browses_job_spec.rb

@@ -31,5 +31,7 @@ describe 'User browses a job', :js do
     page.within('.erased') do
       expect(page).to have_content('Job has been erased')
     end
+
+    expect(build.project.running_or_pending_build_count).to eq(build.project.builds.running_or_pending.count(:all))
   end
 end