Revert "Do not run image tests on php8"
Revert "Do not run image tests on php8"

This reverts commit d690f909284ae4bb4dee7d00318104ee76720bfa.

Signed-off-by: Côme Chilliet <65266482bbd411837c7b5a3a962855e6c075a719@nextcloud.com>

nextcloud/server,nextcloud/server,nextcloud/server,nextcloud/server