[BUGFIX] Fix scrolling to bottom in UpgradeCest test

The JavaScript method "scrollIntoView" does not work
for elements inside a modal or similar. It only
scrolls the main page.

A quick and easy alternative is to set "scrollTop"
to a very high value.

Resolves: #96070
Releases: master, 11.5
Change-Id: Ic5cea96177442acc57ea78cfa66b698c0dfd0f81
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72356


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