[BUGFIX] Migrate mail SMTP encrypt option for symfony/mailer compatibility

SMTP encrypt options were quite a hassle with swiftmailer:
'tls' was used as identifier to start a STARTTLS connection via SMTP
(instead of using SMTPS), while strings like ssl/tlsv1.0/tlsv1.1/tlsv1.2
instructed to use a SSL/TLS connection via SMTPS (without STARTTLS).

symfony/mailer does no longer allow to specify the STARTTLS usage,
as it will use it by default (if the server provides support for it).

Therefore, we now adapt the SMTP encryption configuration setting
via a silent configuration upgrade to avoid that the previous
STARTTLS 'tls' is casted to true while symfony/mailer expects false/null.

While at it, we also fix an incorrect migration for the transport type
'mail'. This wizard didn't work because of a wrong typecast (which has
probably been a copy & paste mistake).

Releases: master
Resolves: #91070
Related: #90295
Change-Id: I7fb1112730fedbbfcdb641c8ce04e17ea925d927
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/64246


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Josef Glatz <josefglatz@gmail.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Josef Glatz <josefglatz@gmail.com>
Reviewed-by: Björn Jacob <bjoern.jacob@tritum.de>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>