How can I increase the maximum file name size of attachments in Prestashop 1.7

On Prestashop 1.7, how can I increase the maximum file name size of attachments?
While naming attachment files in the Back Office, I encounter the following error message.

How can I go around this problem in Prestashop 1.7? I looked up online and found some solutions for Prestashop 1.5 or 1.6, but not for 1.7.

Here are some links that I followed:

• https://www.prestashop.com/forums/topic/63332-bug-the-field-mime-is-too-long-32-chars-max/?tab=comments#comment-1189602
• https://www.prestashop.com/forums/topic/81129-solvedhow-to-change-the-length-of-the-file-name-of-the-attachement/?tab=comments#comment-1197114

Following the above links, I have tried:

• In the DB, changed the 'name' column's type in the 'ps_attachment_lang' table to 'varchar(128)'.
• In Attachment.php (/classes/Attachment.php), made sure the size is 128.

'name' => ['type' => self::TYPE_STRING, 'lang' => true, 'validate' => 'isGenericName', 'required' => true, 'size' => 128],

• In AdminProductsController.php (/controllers/admin/AdminProductsController.php), changed a part of function ajaxProcessAddAttachment(), from

if (!Validate::isGenericName($name)) {
  $_FILES['attachment_file']['error'][] = $this->trans('Invalid name for %s language', [$language['name']], 'Admin.Notifications.Error');
} elseif (Tools::strlen($name) > 32) {
  $_FILES['attachment_file']['error'][] = $this->trans('The name for %1s language is too long (%2d chars max).', [$language['name'], 32], 'Admin.Notifications.Error');
}

to

if (!Validate::isGenericName($name)) {
  $_FILES['attachment_file']['error'][] = $this->trans('Invalid name for %s language', [$language['name']], 'Admin.Notifications.Error');
} elseif (Tools::strlen($name) > 64) {
  $_FILES['attachment_file']['error'][] = $this->trans('The name for %1s language is too long (%2d chars max).', [$language['name'], 64], 'Admin.Notifications.Error');
}

But unfortunately, none of them worked.

Thanks in advance.