[BUGFIX] excludeFromUpdates flag ignored

Since the 6.0 Extension Manager, the "excludeFromUpdates" state
is ignored. It should be checked for and the update button in the
list view hidden in such a case.

Resolves: #51018
Releases: 6.0, 6.1, 6.2
Change-Id: I734331d1b85728dc86732f66ad495a9f83cd0aca
Reviewed-on: https://review.typo3.org/23710
Reviewed-by: Stefan Neufeind
Tested-by: Stefan Neufeind