fixed type hinting for null return (empty SQL result)

Course Grouping: Fix counting non array

OnScreenChat: Prevented display of messages if the username is empty (because of any kind of race condition)

OnScreenChat: Prevented display of messages if the username is empty (because of any kind of race condition)

fixed certificate template version type

Merge branch 'fix/0025577/5-4/SeparatorPreventsHidingMainMenuTopItem' of git.studer-raimann.ch:ILIAS/Core into release_5-4

Richard Klees authored Sep 13, 2019 and Michael Jansen committed Sep 16, 2019

This seems to be no security feature, as the commit message tells, but instead
was previously located (and marked as "dirty hack") in ilCertificate::getFormFieldsFromFO.
In this location it removes stuff (empty lines, especially) that we will need later.