New project form errors out on Cell 2

1. The user will open another browser tab to Cell 2 and navigate to http://localhost:3001/
2. The user will create a new top-level group on Cell 2
3. After creating the new group on Cell 2, Click the New Project button on the group page

Error

NoMethodError - undefined method `id' for nil:NilClass:
  app/views/projects/_new_project_fields.html.haml:28
  app/views/projects/new.html.haml:26
  app/helpers/application_helper.rb:467:in `gitlab_ui_form_for'
  app/views/projects/new.html.haml:25
  app/controllers/application_controller.rb:161:in `render'
  ee/lib/gitlab/ip_address_state.rb:10:in `with'
  ee/app/controllers/ee/application_controller.rb:45:in `set_current_ip_address'
  app/controllers/application_controller.rb:520:in `set_current_admin'
  lib/gitlab/session.rb:11:in `with_session'
  app/controllers/application_controller.rb:511:in `set_session_storage'
  lib/gitlab/i18n.rb:107:in `with_locale'
  lib/gitlab/i18n.rb:113:in `with_user_locale'
  app/controllers/application_controller.rb:502:in `set_locale'
  app/controllers/application_controller.rb:495:in `set_current_context'
  lib/gitlab/metrics/elasticsearch_rack_middleware.rb:16:in `call'
  lib/gitlab/middleware/memory_report.rb:13:in `call'
  lib/gitlab/middleware/speedscope.rb:13:in `call'
  lib/gitlab/query_limiting/middleware.rb:17:in `block in call'
  lib/gitlab/query_limiting/transaction.rb:45:in `run'
  lib/gitlab/query_limiting/middleware.rb:16:in `call'
  lib/gitlab/middleware/rails_queue_duration.rb:33:in `call'
  lib/gitlab/etag_caching/middleware.rb:21:in `call'
  lib/gitlab/metrics/rack_middleware.rb:16:in `block in call'
  lib/gitlab/metrics/web_transaction.rb:46:in `run'
  lib/gitlab/metrics/rack_middleware.rb:16:in `call'
  lib/gitlab/jira/middleware.rb:19:in `call'
  lib/gitlab/middleware/go.rb:20:in `call'
  lib/gitlab/middleware/query_analyzer.rb:11:in `block in call'
  lib/gitlab/database/query_analyzer.rb:37:in `within'
  lib/gitlab/middleware/query_analyzer.rb:11:in `call'
  lib/gitlab/middleware/multipart.rb:173:in `call'
  lib/gitlab/middleware/read_only/controller.rb:50:in `call'
  lib/gitlab/middleware/read_only.rb:18:in `call'
  lib/gitlab/middleware/same_site_cookies.rb:27:in `call'
  lib/gitlab/middleware/basic_health_check.rb:25:in `call'
  lib/gitlab/middleware/path_traversal_check.rb:25:in `call'
  lib/gitlab/middleware/handle_malformed_strings.rb:21:in `call'
  lib/gitlab/middleware/handle_ip_spoof_attack_error.rb:25:in `call'
  lib/gitlab/middleware/request_context.rb:15:in `call'
  lib/gitlab/middleware/webhook_recursion_detection.rb:15:in `call'
  config/initializers/fix_local_cache_middleware.rb:11:in `call'
  lib/gitlab/middleware/compressed_json.rb:44:in `call'
  lib/gitlab/middleware/static.rb:11:in `call'
  lib/gitlab/webpack/dev_server_middleware.rb:34:in `perform_request'
  lib/gitlab/middleware/rack_multipart_tempfile_factory.rb:19:in `call'
  lib/gitlab/middleware/sidekiq_web_static.rb:20:in `call'
  lib/gitlab/metrics/requests_rack_middleware.rb:79:in `call'
  lib/gitlab/middleware/release_env.rb:13:in `call'

Suggested fix

Assuming we adopt #427730, the suggested fix is to return nil here when the setting Allow users to create personal namespaces in this Organization for that organization is disabled

Update to use current_user.namespace_id, see if the pipeline is green. Test different new project forms to see if they still work