Fix shadeExpansion being 0 when QS partially expanded

The shadeExpansion should gradually decrease as QS are being expanded.

I checked the usages of this flow to make sure this change is safe to
make unflagged, and I saw that they fall into 3 categories:
1) They need to know if either the shade or qs are expanded, so this
change would be a no-op for them
2) They assume that shadeExpansion and qsExpansion are complementary
(and this fix makes that actually true)
3) They use the SceneContainer implementation, so this change wouldn't
affect them

Bug: 330143161
Test: ShadeInteractorLegacyImplTest
Flag: NONE
Change-Id: Id3b3a12be5b7ed284e5947bc9eabda020519086a