[TASK] Make ImageDimensionTest phpunit 10 ready

* Static DP
* Avoid withConsecutive() - kinda useless in
  this case anyways
* Don't use $this in DP

Resolves: #100320
Related: #100249
Releases: main
Change-Id: Ia1fbdf1152786037f5bb9c9295ed3f57491000d5
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/78274


Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>