[Bug]: emailer pref is always set to php if you save bulkmailer preferences

[Jimmi08]

What e107 version are you using?

v2.3.3

Bug description

If you save bulkmailer preferences (f.e. smtp), your emailer preference is always set to PHP.

How to reproduce

1. Go to Preferences, select Emailer SMTP.
2. Go to Users/Mail/Preferences, select SMTP and save
3. Return back to Preferences and your emailer is PHP

Expected behavior

Don't change Emailer settings by saving other preferences

What browser(s) are you seeing the problem on?

Chrome / Brave

PHP Version

8.2

[Jimmi08]

It is the long time issue, I noticed this behavior in 2020: #4123

The reason for this bug is this code in mailout.php
if (!in_array($_POST['mailer'], array('smtp', 'sendmail', 'php'))) $_POST['mailer'] = 'php';
In this file, there is no mailer field if $_POST, only bulkmailer Or it should be a hidden field with this test.