[!!!][TASK] Use fallbacks for AbstractWidgetController view-configuration

The fallback-paths functionality offered by the parent class
is now available for Fluid-widgets.

Change-Id: I73d3a792b261502b1eafd92b3b7b514e049e6ac2
Resolves: #59505
Releases: master
Reviewed-on: http://review.typo3.org/30672


Reviewed-by: Stefan Neufeind <typo3.neufeind@speedpartner.de>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>