[TASK] Migrate deprecated PHPUnit 9 methods

Since the recent release of PHPUnit 9.6 some new deprecations were added
which signal breaking changes for version 10. As deprecations are
causing our tests to fail, they need to be addressed immediately.

Method `expectErrorMessage` replaced with `expectExceptionMessage`.
Method `getMockClass` replaced with `createMock` and a subsequent
get_class call.

Also update phpunit/phpunit to latest version:
> composer update phpunit/phpunit
> composer bump phpunit/phpunit

Resolves: #99817
Releases: main, 11.5
Change-Id: I6d01ccca398a8ff5db735a35b19061b711c843cc
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/77692


Tested-by: Benjamin Franzke <bfr@qbus.de>
Tested-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benjamin Franzke <bfr@qbus.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Stefan Bürk <stefan@buerk.tech>