[CLEANUP] Replace count with empty in multiple extensions, part III

Replace occurences of count() with matching empty() pendants.
Affected extensions:
- scheduler
- sv
- version
- workspaces

Resolves: #67955
Releases: master
Change-Id: I1fd152ed9b581e0f2645837776fd7fab1ccbf73e
Reviewed-on: http://review.typo3.org/40959


Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Stephan Großberndt <stephan@grossberndt.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>