Fix duplicated pasted events when the selection contains an event and its sub-events

[D8H]

No description provided.

[4ian]

Not sure if useful, but could you use contains:

GDevelop/Core/GDCore/Events/EventsList.h

Lines 138 to 144 in 6377ece

	/**
	* Return true if the specified event exists in the list.
	* \param event The event to searched for
	* \param recursive Set it to false to prevent sub events to be inspected.
	*/
	bool Contains(const gd::BaseEvent& eventToSearch,
	bool recursive = true) const;

(maybe not because you don't have an EventsList).

[D8H]

I use a Set to avoid checking every selected items (S) with every children (C) of every selected items (S). Instead, I fill the set with every children (C) of every selected items (S). So, it's O(C * S) instead of O(C * S²)