[TASK] Replace GU::getIndpEnv('TYPO3_SSL') with normalizeParam option

This one occurence of the infamous getIndpEnv method can be replaced with
the requests normalizedParams information.

Resolves: #93861
Releases: master
Change-Id: I8afeae1b9a07738205f6841f67d372e7b67a045c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/67493


Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benjamin Franzke <bfr@qbus.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Benjamin Franzke <bfr@qbus.de>