[571875] disabled change type in viewer background

reworked the test method isViewer to take the receiver list into account
rather than relying on the fbnetwork

Bug: https://bugs.eclipse.org/bugs/show_bug.cgi?id=571875
Change-Id: I28eee58e1dcd4903d46886b0d279f85d810fda2c
Signed-off-by: Lukas Wais <lukas.wais@jku.at>