[TASK] Update `phpstan/phpstan` to 1.10.47

Also fix one unneeded null coalescing operator usage,
which was discovered with this release.

> composer require --dev phpstan/phpstan:^1.10.47

Resolves: #102584
Releases: main, 12.4
Change-Id: I19876bfe33fcf05166df7e0d92696c2368b29490
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82068


Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>