Enable frozen string for spec/tasks

Partially addresses:

https://gitlab.com/gitlab-org/gitlab/issues/27703

spec/db/production/settings_spec.rb

+# frozen_string_literal: true
+
 require 'spec_helper'
 require 'rainbow/ext/string'
 

spec/tasks/cache/clear/redis_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'clearing redis cache' do

spec/tasks/config_lint_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 Rake.application.rake_require 'tasks/config_lint'
 

spec/tasks/gitlab/artifacts/check_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:artifacts rake tasks' do

spec/tasks/gitlab/artifacts/migrate_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:artifacts namespace rake task' do

spec/tasks/gitlab/backup_rake_spec.rb

+# frozen_string_literal: true
+
 require 'spec_helper'
 require 'rake'
 

spec/tasks/gitlab/check_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'check.rake' do

spec/tasks/gitlab/cleanup_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:cleanup rake tasks' do

spec/tasks/gitlab/db_rake_spec.rb

+# frozen_string_literal: true
+
 require 'spec_helper'
 require 'rake'
 

spec/tasks/gitlab/git_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:git rake tasks' do

spec/tasks/gitlab/gitaly_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:gitaly namespace rake task' do

spec/tasks/gitlab/info_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:env:info' do

spec/tasks/gitlab/ldap_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:ldap:rename_provider rake task' do

spec/tasks/gitlab/lfs/check_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:lfs rake tasks' do

spec/tasks/gitlab/lfs/migrate_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:lfs namespace rake task' do

spec/tasks/gitlab/shell_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:shell rake tasks' do

spec/tasks/gitlab/storage_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'rake gitlab:storage:*', :sidekiq do

spec/tasks/gitlab/task_helpers_spec.rb

+# frozen_string_literal: true
+
 require 'spec_helper'
 
 class TestHelpersTest

spec/tasks/gitlab/uploads/check_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:uploads rake tasks' do

spec/tasks/gitlab/uploads/migrate_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:uploads:migrate and migrate_to_local rake tasks' do

spec/tasks/gitlab/web_hook_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:web_hook namespace rake tasks' do

spec/tasks/gitlab/workhorse_rake_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'gitlab:workhorse namespace rake task' do

spec/tasks/tokens_spec.rb

+# frozen_string_literal: true
+
 require 'rake_helper'
 
 describe 'tokens rake tasks' do