delete notification and notification_user when validate

app/Models/Notification.php

@@ -12,6 +12,11 @@ class Notification extends Model
 
     public function users(): \Illuminate\Database\Eloquent\Relations\BelongsToMany
     {
-        return $this->belongsToMany(User::class, 'notification_user', 'notification_id', 'user_id');
+        return $this->belongsToMany(
+            User::class,
+            'notification_user',
+            'notification_id',
+            'user_id'
+        )->withTimestamps();
     }
 }

app/Models/User.php

@@ -57,6 +57,11 @@ class User extends Authenticatable
 
     public function notifications(): \Illuminate\Database\Eloquent\Relations\BelongsToMany
     {
-        return $this->belongsToMany(Notification::class, 'notification_user', 'user_id', 'notification_id');
+        return $this->belongsToMany(
+            Notification::class,
+            'notification_user',
+            'user_id',
+            'notification_id'
+        )->withTimestamps();
     }
 }