Fix Rubocop Style/PercentLiteralDelimiters offence

.rubocop_todo/style/percent_literal_delimiters.yml

metrics_server/metrics_server.rb

spec/tasks/gitlab/db_rake_spec.rb

spec/tooling/danger/customer_success_spec.rb

spec/tooling/danger/datateam_spec.rb

spec/tooling/danger/sidekiq_queues_spec.rb

spec/tooling/lib/tooling/test_map_generator_spec.rb

spec/uploaders/attachment_uploader_spec.rb

spec/uploaders/avatar_uploader_spec.rb

spec/uploaders/ci/pipeline_artifact_uploader_spec.rb

spec/uploaders/dependency_proxy/file_uploader_spec.rb

...oaders/design_management/design_v432x230_uploader_spec.rb

spec/uploaders/external_diff_uploader_spec.rb

spec/uploaders/import_export_uploader_spec.rb

spec/uploaders/job_artifact_uploader_spec.rb

spec/uploaders/lfs_object_uploader_spec.rb

spec/uploaders/namespace_file_uploader_spec.rb

spec/uploaders/object_storage_spec.rb

spec/uploaders/packages/composer/cache_uploader_spec.rb

...uploaders/packages/debian/component_file_uploader_spec.rb