[TASK] Drop fallback for explode calls in GeneralUtility

In PHP < 8.0, `explode` could return `false`. Starting with PHP 8.0,
`explode` will always return an array. Hence, no check and fallback
for `false` is needed anymore.

Resolves: #99178
Releases: main
Change-Id: Ie2a3df3c50892c8d198ce91eff2106b9a28efc9d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/76804


Tested-by: core-ci <typo3@b13.com>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Nikita Hovratov <nikita.h@live.de>
Reviewed-by: Nikita Hovratov <nikita.h@live.de>