[!!!][TASK] Remove outdated hook in GifBuilder

A hook in GifBuilder from 2003, when TYPO3 3.8.0
was released, is removed without substitution.

This hook has no real benefit anymore,
and the referenced extension "julle_gifbconf"
does not exist anymore in TER.

Resolves: #102931
Releases: main
Change-Id: I757fd6f60b2e231523779c703d746380afd99704
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82649


Tested-by: core-ci <typo3@b13.com>
Tested-by: Simon Schaufelberger <simonschaufi+typo3@gmail.com>
Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Guido Schmechel <guido.schmechel@brandung.de>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Simon Schaufelberger <simonschaufi+typo3@gmail.com>
Tested-by: Benni Mack <benni@typo3.org>