[BUGFIX] Correctly display the CGI environment in Environment module

During the TYPO3 v9 install tool refactoring, a simple PHP array syntax
mistake did not correctly set the fluid variable "systemInformationCgiDetected"
which always resulted in not running in a CGI environment.

The change adapts the array variable assigment.

Resolves: #87320
Releases: master, 9.5
Change-Id: I2368ff033a6318d67c9153be20816d13ad8bd08d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/62837


Reviewed-by: Susanne Moog <look@susi.dev>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Reviewed-by: Michael Schams <typo3@2018.schams.net>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Michael Schams <typo3@2018.schams.net>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Benni Mack <benni@typo3.org>