Unified preloading stylesheets

Changelog: changed
MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/67045

app/views/layouts/_head.html.haml

@@ -32,10 +32,6 @@
   - if page_canonical_link
     %link{ rel: 'canonical', href: page_canonical_link }
 
-  - if user_application_theme == 'gl-dark'
-    = preload_link_tag(path_to_stylesheet('application_utilities_dark'))
-  - else
-    = preload_link_tag(path_to_stylesheet('application_utilities'))
   = yield :prefetch_asset_tags
 
   = favicon_link_tag favicon, id: 'favicon', data: { original_href: favicon }, type: 'image/png'

app/views/layouts/_loading_hints.html.haml

 = cache_if(Feature.enabled?(:cached_loading_hints, current_user), [ActionController::Base.asset_host, user_application_theme, user_color_scheme], expires_in: 1.minute) do
+  - css_crossorigin = ActionController::Base.asset_host ? 'anonymous' : nil
+
   - if ActionController::Base.asset_host
     %link{ rel: 'dns-prefetch', href: ActionController::Base.asset_host }
     %link{ rel: 'preconnect', href: ActionController::Base.asset_host, crossorigin: '' }
   - if user_application_theme == 'gl-dark'
-    %link{ { rel: 'preload', href: stylesheet_url('application_dark'), as: 'style' }, ActionController::Base.asset_host ? { crossorigin: 'anonymous' } : {} }
+    = preload_link_tag(path_to_stylesheet('application_utilities_dark'), crossorigin: css_crossorigin)
+    = preload_link_tag(path_to_stylesheet('application_dark'), crossorigin: css_crossorigin)
   - else
-    %link{ { rel: 'preload', href: stylesheet_url('application'), as: 'style' }, ActionController::Base.asset_host ? { crossorigin: 'anonymous' } : {} }
-  %link{ { rel: 'preload', href: stylesheet_url("highlight/themes/#{user_color_scheme}"), as: 'style' }, ActionController::Base.asset_host ? { crossorigin: 'anonymous' } : {} }
+    = preload_link_tag(path_to_stylesheet('application_utilities'), crossorigin: css_crossorigin)
+    = preload_link_tag(path_to_stylesheet('application'), crossorigin: css_crossorigin)
+  = preload_link_tag(path_to_stylesheet("highlight/themes/#{user_color_scheme}"), crossorigin: css_crossorigin)
   - if Gitlab::Tracking.enabled? && Gitlab::CurrentSettings.snowplow_collector_hostname
     %link{ rel: 'preconnect', href: Gitlab::CurrentSettings.snowplow_collector_hostname, crossorigin: '' }