[BUGFIX] Check for complete database configuration before connecting

Install tool has been trying to connect to the database before
checking if a bare minimum of configuration is given to. This has
been done to decide if the database connect step needs to be shown.

Starting with php8.1 this fails hard and the step is not shown,
thus an installation cannot be finished.

This patch change the checking order and checks for the bare minimum of
configuration first, before try to connect to the database.

Build/Scripts/runTests.sh -s acceptanceInstall -p 8.1 -d sqlite
Build/Scripts/runTests.sh -s acceptanceInstall -p 8.1 -d mariadb
Build/Scripts/runTests.sh -s acceptanceInstall -p 8.1 -d mysql

Resolves: #95545
Releases: master, 10.4
Change-Id: I9923198b26f86e44fd6c1f6655195faa0c79895e
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73652


Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Benni Mack <benni@typo3.org>