Use new steal predicate in TableManagementHelpers

lib/gitlab/database/partitioning_migration_helpers/table_management_helpers.rb

@@ -164,8 +164,8 @@ module Gitlab
               "this could indicate the previous partitioning migration has been rolled back."
           end
 
-          Gitlab::BackgroundMigration.steal(MIGRATION_CLASS_NAME) do |raw_arguments|
-            JobArguments.from_array(raw_arguments).source_table_name == table_name.to_s
+          Gitlab::BackgroundMigration.steal(MIGRATION_CLASS_NAME) do |background_job|
+            JobArguments.from_array(background_job.args.second).source_table_name == table_name.to_s
           end
 
           primary_key = connection.primary_key(table_name)

spec/lib/gitlab/database/partitioning_migration_helpers/table_management_helpers_spec.rb

@@ -513,7 +513,7 @@ RSpec.describe Gitlab::Database::PartitioningMigrationHelpers::TableManagementHe
     context 'finishing pending background migration jobs' do
       let(:source_table_double) { double('table name') }
       let(:raw_arguments) { [1, 50_000, source_table_double, partitioned_table, source_column] }
-      let(:background_job) { double('background job', args: raw_arguments) }
+      let(:background_job) { double('background job', args: ['background jobs', raw_arguments]) }
 
       before do
         allow(migration).to receive(:table_exists?).with(partitioned_table).and_return(true)