Partial revert to align with 8.x-3.x "Issue #2992362 by thalles, Daniel Korte,...

Partial revert to align with 8.x-3.x "Issue #2992362 by thalles, Daniel Korte, sagannotcarl, baikho, osman, japerry, stevekeiretsu: Wizards should be using PrivateTempStore not SharedTempStore, otherwise all users end up sharing the same cached form values"