[BUGFIX] Set extension name in Fluid context

Resolves: #84697
Related: #83987
Releases: master
Change-Id: I292b5942144c1453921ba7ce490e26209dee187f
Reviewed-on: https://review.typo3.org/56635


Reviewed-by: Mathias Brodala <mbrodala@pagemachine.de>
Reviewed-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: Georg Ringer <georg.ringer@gmail.com>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Tymoteusz Motylewski <t.motylewski@gmail.com>
Tested-by: Tymoteusz Motylewski <t.motylewski@gmail.com>