Merge pull request #4719 from nextcloud/error-page-theming

ensure theming app is loaded when showing an error page

lib/private/legacy/template.php

@@ -292,6 +292,11 @@ class OC_Template extends \OC\Template\Base {
 		* @param string $hint An optional hint message - needs to be properly escaped
 		*/
 	public static function printErrorPage( $error_msg, $hint = '' ) {
+		if (\OC_App::isEnabled('theming') && !\OC_App::isAppLoaded('theming')) {
+			\OC_App::loadApp('theming');
+		}
+
+
 		if ($error_msg === $hint) {
 			// If the hint is the same as the message there is no need to display it twice.
 			$hint = '';