[!!!][TASK] Remove non-factory init of RenderingContext

Removes a Services.yaml entry from ext:fluid to enforce
using RenderingContextFactory->create().

Change-Id: Ibd02cc394b99cb72856c3828b13a06e244544576
Resolves: #96271
Related: #94285
Releases: main
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72541


Tested-by: Benjamin Franzke <bfr@qbus.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benjamin Franzke <bfr@qbus.de>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>