Fix broadcast messages

The broadcast message shown in the AddBrickFragment should either be the default message or, if the default message has been auto-removed, the first broadcast message in the list. This fix will do that.

http://catrobatgw.ist.tugraz.at:8080/job/Catroid-custom-branch-test/1238/
And because the BroadcastBricksTest fails at the last line (and I still don't know why), an individual testrun
http://catrobatgw.ist.tugraz.at:8080/job/Catroid-single-UI-test/865/