Frameworks: SlimRecents: Make expanded layout pretty

Instead of adding an extra box below the header expand it in the inner layout
so it is visual one card. Looks nicer, conform with google style and saves
a bit space

Change-Id: I6b406c622ac557a1ce6b81bfa86b4c96b492eceb

Conflicts:
	packages/SystemUI/res/values-holodark/colors.xml
	packages/SystemUI/res/values/dimens.xml