#3468192 - Make more dynamic PageTop->alter()

Closes #3468192

src/HookHandler/PageTop.php

@@ -53,8 +53,8 @@ class PageTop implements ContainerInjectionInterface {
    * @param array $page_top
    *   The page top elements.
    */
-  public function alter(array &$page_top): void {
-    $ui_skins_css_variables_settings = \theme_get_setting(UiSkinsInterface::CSS_VARIABLES_THEME_SETTING_KEY);
+  public function alter(array &$page_top, $theme = NULL): void {
+    $ui_skins_css_variables_settings = \theme_get_setting(UiSkinsInterface::CSS_VARIABLES_THEME_SETTING_KEY, $theme);
     if (!\is_array($ui_skins_css_variables_settings)) {
       return;
     }