[BUGFIX] Check access to cshmanual module

Don't render the "more" link in the help popup if the user has no
access to the cshmanual module.

Resolves: #73013
Related: #73009
Releases: master, 7.6
Change-Id: I5b236c08fd505c1f405a3fc0e459c1ac21fbeb84
Reviewed-on: https://review.typo3.org/46358


Reviewed-by: Daniel Goerz <ervaude@gmail.com>
Tested-by: Daniel Goerz <ervaude@gmail.com>
Reviewed-by: Gianluigi Martino <gmartino27@gmail.com>
Tested-by: Gianluigi Martino <gmartino27@gmail.com>
Reviewed-by: Andreas Fernandez <typo3@scripting-base.de>
Tested-by: Andreas Fernandez <typo3@scripting-base.de>