Immersive: Update global tile drawables

Bigger arrows, thanks to Lo Huot for the drawables.

Signed-off-by: Carlo Savignano <stevewatersy@gmail.com>

Conflicts:
	packages/SystemUI/res/drawable-hdpi/ic_qs_immersive_global_on.png
	packages/SystemUI/res/drawable-mdpi/ic_qs_immersive_global_on.png
	packages/SystemUI/res/drawable-xhdpi/ic_qs_immersive_global_on.png
	packages/SystemUI/res/drawable-xxhdpi/ic_qs_immersive_global_on.png