Revert "Allow notifications without ticker text to show in Halo"

This reverts commit 690b4b4448c70cbd6c5b12150db4cc91678d17d2.

Conflicts:
	packages/SystemUI/src/com/android/systemui/statusbar/tablet/TabletTicker.java

Change-Id: I6ee8c5d1264b57e114a349539de54d766e90dc76
Revert "Adjust tablet notification handling when halo is enabled"

This reverts commit 6078b337183a421e694aec2f37b02b7a83de3b97.