Critical error : MailCollector with an email who contain empty subject

[mat44444]

Describe the bug

When a email with empty subject is in MailCollector box we got:
Blank page when launch manually the process,
Or the job is stunc in status: In process in the automatic job

Page(s) URL

If applicable, page(s) URL where the bug happens.

To reproduce

Steps to reproduce the behavior:

1. Have a working MailCollector on a configured mailbox
2. Send a email with empty subject
3. Force the mail collector to launch
4. See error

Expected behavior

At least, handle the error, log a warning and skip the mail.
The better option, should be replys to the sender and said the request could not be handle because there not subject in email and flush the email

Logs

[2020-08-26 13:05:15] glpiphplog.CRITICAL:   *** Uncaught Exception Laminas\Mail\Storage\Exception\InvalidArgumentException: Header with Name subject or subject not found in /opt/www/gri.dmz.urgences-sante.qc.ca/html/vendor/laminas/laminas-mail/src/Storage/Part.php at line 307
  Backtrace :
  ...r/laminas/laminas-mail/src/Storage/Part.php:376 Laminas\Mail\Storage\Part->getHeader()
  inc/mailcollector.class.php:1035                   Laminas\Mail\Storage\Part->__get()
  inc/mailcollector.class.php:734                    MailCollector->buildTicket()
  front/mailcollector.form.php:77                    MailCollector->collect()
  

Screenshots

If applicable, add screenshots to help explain your problem.

Your GLPI setup (you can find it in Setup > General menu, System tab)

Additional context

Add any other context about the problem here.

[cedric-anne]

Hi,

It duplicates #7790 and has been fixed in #7748.

Regards