Update split shade signal reference

This is probably a regression since wallpaper zoom out isn't happening either on the outer screen of foldables. We should have updated the isSplitShade signal to the new *Interactor architecture.

Fixes: 401283527
Test: manual
Flag: EXEMPT bugfix
Change-Id: I7bb617822db65502e3b83c313f484b8c69c34cd8