[BUGFIX] Don't assign undefined variable to template of Dashboard

As $this->settings is not defined, it should not be passed to the Fluid
template of the DashboardController.

Resolves: #90453
Releases: master
Change-Id: Idc946da7d293311215c2bf318dc6959e5f6f080f
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63337


Tested-by: Daniel Siepmann <coding@daniel-siepmann.de>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Daniel Siepmann <coding@daniel-siepmann.de>
Reviewed-by: Koen Wouters <koen.wouters@maxserv.com>
Reviewed-by: Benni Mack <benni@typo3.org>