[TASK] Use strict comparison for strings

Change string comparison for string checks. Checks which could lead
to false positives like comparing with '0' or '' are excluded.
RegEx used to find affected places: (?<=\s)((?:!|=)=)(?=[^=]'[^0-9'\n]+')

Resolves: #79540
Resolves: master
Change-Id: I9a04bdd9e0e78cc97036560709bb505097bf48f9
Reviewed-on: https://review.typo3.org/51462


Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>