add entity to addIf function for action buttons

[HelloSebastian]

Before:

'addIf' => function () {
    return true;
}

After:

'addIf' => function ($entity) {
    return true;
}

Example

// UserTable
'addIf' => function (User $user) {
    return $user->isActive();
}

No changing break. Old function call still works.