[5.x] Fix error after deleting role when storing users in the database (

#11069)

src/Auth/Eloquent/User.php

@@ -105,7 +105,7 @@ public function explicitRoles($roles = null)
         return $this->roles = $this->roles
             ?? (new Roles($this))->all()->map(function ($row) {
                 return Role::find($row->role_id);
-            })->keyBy->handle();
+            })->filter()->keyBy->handle();
     }
 
     protected function saveRoles()