Add margin below legacy default clock to account for date weather move

Setting the margin to 2x the height of the date/weather for now
due to the clock moving around in the burn in layer

Bug: 415391096
Test: manual
Flag: com.android.systemui.shared.clock_reactive_smartspace_layout
Change-Id: I3e339c5e4afcf3ccabaf94e6c07fda5f1a8f715e