Remove unsued pipelines-related prometheus metric

lib/gitlab/ci/pipeline/chain/create.rb

@@ -17,27 +17,11 @@ module Gitlab
             end
           rescue ActiveRecord::RecordInvalid => e
             error("Failed to persist the pipeline: #{e}")
-          ensure
-            if pipeline.builds.where(stage_id: nil).any?
-              invalid_builds_counter.increment(node: hostname)
-            end
           end
 
           def break?
             !pipeline.persisted?
           end
-
-          private
-
-          def invalid_builds_counter
-            @counter ||= Gitlab::Metrics
-              .counter(:gitlab_ci_invalid_builds_total,
-                       'Invalid builds without stage assigned counter')
-          end
-
-          def hostname
-            @hostname ||= Socket.gethostname
-          end
         end
       end
     end