[BUGFIX] Correct signature in ArrayUtility::isValidPath

In #97202 types for the class ArrayUtility were added.
Unfortunately the second parameter ($path) for the method
isValidPath was changed to string only.
The method basically calls getValueByPath, which has
$path defined as array|string and handles it properly.
It makes no sense, not to be able to call isValidPath
with the same types for the $path argument.

Resolves: #100302
Releates: #97202
Releases: main
Change-Id: I7b0235d3013c84a6580397162de8f65dea212cda
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78258


Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>