Change constant from class to module

ee/lib/ee/gitlab/background_migration/populate_resolved_on_default_branch_column.rb

@@ -3,9 +3,9 @@
 module EE
   module Gitlab
     module BackgroundMigration
-      class PopulateResolvedOnDefaultBranchColumn
-        def perform(project_ids)
-          project_ids.each { |project_id| PopulateResolvedOnDefaultBranchColumnForProject.perform(project_id) }
+      module PopulateResolvedOnDefaultBranchColumn
+        def perform(*project_ids)
+          project_ids.flatten.each { |project_id| PopulateResolvedOnDefaultBranchColumnForProject.perform(project_id) }
         end
 
         module Routable

ee/spec/lib/ee/gitlab/background_migration/populate_resolved_on_default_branch_column_spec.rb

@@ -2,7 +2,7 @@
 
 require 'spec_helper'
 
-RSpec.describe EE::Gitlab::BackgroundMigration::PopulateResolvedOnDefaultBranchColumn do
+RSpec.describe ::Gitlab::BackgroundMigration::PopulateResolvedOnDefaultBranchColumn do
   let(:users) { table(:users) }
   let(:namespaces) { table(:namespaces) }
   let(:projects) { table(:projects) }

lib/gitlab/background_migration/populate_resolved_on_default_branch_column.rb

@@ -9,4 +9,4 @@ module Gitlab
   end
 end
 
-Gitlab::BackgroundMigration::UpdateVulnerabilityConfidence.prepend_if_ee('EE::Gitlab::BackgroundMigration::PopulateResolvedOnDefaultBranchColumn')
+Gitlab::BackgroundMigration::PopulateResolvedOnDefaultBranchColumn.prepend_if_ee('EE::Gitlab::BackgroundMigration::PopulateResolvedOnDefaultBranchColumn')