An attempt to fix #110834

Issue:

• Mouse pointer still changes appearance when hovering over the invisible (folded) part of a FoldableContainer

Solution:

• Override Control::has_point so that when folded, only the title rect is considered interactive. When unfloded, the default Control logic is used.

Notes:

• I copied the title rect logic from FoldableContainer::gui_input. This rect is being created 4 times (including my addition) across _notification, gui_input and now has_point. It might be useful to cache this and update on some size change event, or at the very least refactor the logic into a helper function.