Partially revert "Launcher3: some tweaks to the default setup"

Hangouts is not the default AOSP SMS app and is not included in gapps,
resulting in blank space in the hotseat.
We should not depend on play store apps for the default workspace configuration.

This reverts commit ab4f83b52e3fe54822e2dc696c611f0961dc8702.

Change-Id: Iefe2244d981ce1e006a8cca6c3db1b2c8b606848