[REFACTOR] cleaned up and renamed classes in ui.expressions package

Cleaned up the if/else blocks and renamed BuddyProperyTest and
ParticipantPropertyTest class.

Change-Id: If0a0041292a4df70ef98133ba23173eb6af28ca4
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1678
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>