[BUGFIX] Fix various "No pseudo-site found in root line of page" errors

Fixes workspace resolving etc.

The !empty statement is wrong as a string value "0" would not expect the
right return. This fixes the detection of l10n_parent.
Also check for sys_language_uid, too, to get the pid of the record
instead of its parent.

This also fixes opening categories (sys_category) when using EXT:news,
which calls this condition in TCA:
'displayCond' => 'USER:' . \TYPO3\CMS\Core\Compatibility\
PseudoSiteTcaDisplayCondition::class . '->isInPseudoSite:pages:false',

Check array index exists in SiteResolving.

Resolves: #79606
Resolves: #86186
Resolves: #86622
Resolves: #86678
Resolves: #86684
Releases: master, 9.5
Change-Id: If3ddf5eead2dddd51db3bcf751d71d3bc362ef35
Reviewed-on: https://review.typo3.org/59229


Tested-by: TYPO3com <noreply@typo3.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>