Fix duplicate entry.

classes/output/icon_system_fontawesome.php

@@ -218,13 +218,12 @@ public function get_core_icon_map() {
             'core:i/cohort' => 'fas fa-users',
             'core:i/competencies' => 'far fa-check-square',
             'core:i/completion_self' => 'far fa-user',
-            'core:i/dashboard' => 'fas fa-tachometer-alt',
-            'core:i/lock' => 'fas fa-lock',
             'core:i/categoryevent' => 'fas fa-cubes',
             'core:i/contentbank' => 'fas fa-paint-brush',
             'core:i/course' => 'fas fa-graduation-cap',
             'core:i/courseevent' => 'fas fa-university',
             'core:i/customfield' => 'far fa-hand-point-right',
+            'core:i/dashboard' => 'fas fa-tachometer-alt',
             'core:i/db' => 'fas fa-database',
             'core:i/delete' => 'fas fa-trash',
             'core:i/down' => 'fas fa-arrow-down',