Disable Saving App Pairs for Private Space Apps

This change disables saving App Pair from recents
into launcher workspace when any of the app in pair
belongs to Private Space.
Private Space are still allowed in Split Mode

Bug: 322892793
Test: Manual on device
Flag: ACONFIG com.android.launcher3.private_space_restrict_accessibility_drag TRUNKFOOD
Change-Id: I204b721ce3a2bf4ebfd7419c25d72a77fd8174ac