MDL-57791 testing: Add missing cachedef lang string

lang/en/cache.php

@@ -57,6 +57,7 @@
 $string['cachedef_message_time_last_message_between_users'] = 'Time created for most recent message between users';
 $string['cachedef_locking'] = 'Locking';
 $string['cachedef_message_processors_enabled'] = "Message processors enabled status";
+$string['cachedef_modelswithpredictions'] = 'Models with available predictions';
 $string['cachedef_navigation_expandcourse'] = 'Navigation expandable courses';
 $string['cachedef_observers'] = 'Event observers';
 $string['cachedef_plugin_functions'] = 'Plugins available callbacks';