Launcher3Go should override Launcher3QuickStep

Now that Launcher3QuickStep is the default launcher,
Launcher3Go should override Launcher3QuickStep as well
else Go targets will have both Launcher3Go and
Launcher3QuickStep apks installed in system image.

Also, Launcher3QuickStepGo should override Launcher3QuickStep.

BUG: 113564404

Test: With this, on Go targets where Launcher3Go is
      included in PRODUCT_PACKAGES, only one apk i.e. Launcher3Go
      will be present in /system/priv-app.

Change-Id: I84d2e3c23c5acdced70d028e9518e04834577049