[TASK] Raise typo3/testing-framework

Casual raise of v6 typo3/testing-framework.

> composer req --dev mikey179/vfsstream:^1.6.11
> composer req --dev typo3/testing-framework:^6.16.6

Change-Id: I4761948bd8827ab4638f280d5b69403d300afcb1
Resolves: #98026
Releases: main, 11.5, 10.4
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75294


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