[BUGFIX] Set „scanned“ flag when scanning all extensions

Resolves: #85504
Releases: master
Change-Id: I75580fb05c0217b1c28a2109b7f6bc2147d458d8
Reviewed-on: https://review.typo3.org/57494


Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>