[BUGFIX] Correct LaTeX setup

The LaTeX setup in Settings.yml was copied was extension
"sphinx", which uses some special settings. Furthermore
the extension name was wrong, thus breaking the PDF rendering.

Resolves: #59386
Releases: 2.3
Change-Id: I9b196a4d9c82f923848c1d8abb03b23438b709e2
Reviewed-on: https://review.typo3.org/30877
Reviewed-by: Francois Suter
Tested-by: Francois Suter