IsItemHovered(): fixed return value false positive when used after EndChild(), EndGroup() or widgets using either... (#3851, #1370)

...when the hovered location is located within a child window, e.g. InputTextMultiline().
This is intended to have no side effects, but brace yourself for the possible comeback..
This essentially makes IsItemHovered() not accept hover from child windows, but EndChild/EndGroup are forwarded.
More or less should fix/revert c76f014292 which was a revert of 344d48be3
3 files changed