[BUGFIX] Allow felogin to work without storage PID

With the system-wide configuration option $GLOBALS['TYPO3_CONF_VARS']['FE']['checkFeUserPid']
set to false, EXT:felogin now allows to still render the form,
instead of throwing a runtime exception before.

Resolves: #84269
Releases: master, 9.5
Change-Id: Id0f0692d33e423929d41b9cdd5401b72cfdf77b0
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/62916


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Daniel Goerz <daniel.goerz@posteo.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Reviewed-by: Daniel Goerz <daniel.goerz@posteo.de>