[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.
Move test with deprecations to UnitDeprecated and remove expectation.

Also update phpunit/phpunit and dependencies to latest version:
> composer req --dev phpunit/phpunit:^9.6.1 -W

Resolves: #99817
Releases: main, 11.5
Change-Id: I6d01ccca398a8ff5db735a35b19061b711c843cc
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/77693


Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>