Address deprecation warnings in spec/services/issues/bulk_update_service_spec.rb

› bundle exec rspec spec/services/issues/bulk_update_service_spec.rb
DEPRECATION WARNING: Passing a nested array to Active Record finder methods is deprecated and will be removed. Flatten your array before using it for 'IN' conditions. (called from execute at /gitlab/app/services/issues/bulk_update_service.rb:11)

The fix is to replace

issues_ids: @issues.map(&:id)

by

issues_ids: @issues.map(&:id).join(",")

and

issues_ids: [issue.id]

by

issues_ids: issue.id.to_s

in spec/services/issues/bulk_update_service_spec.rb since we're splitting the ids in Issues::BulkUpdateService:

issues_ids   = params.delete(:issues_ids).split(",")