AnimationNodeBlendTreeEditor: Missing Copy and Paste functionality.

[RonYanDaik]

Godot version

4.x

System information

Doesn't matter.

Issue description

animation_blend_tree_editor_plugin.cpp has this code implying that you can paste data from clipboard.

Ref<AnimationNode> clipb = EditorSettings::get_singleton()->get_resource_clipboard();
	if (clipb.is_valid()) {
		add_node->get_popup()->add_separator();
		add_node->get_popup()->add_item(TTR("Paste"), MENU_PASTE);
	}

But there is no copy functionality to be found.
Copy option in menu is missing nor keyboard shortcuts exist.

Steps to reproduce

N/A

Minimal reproduction project

Repository Code.

[Calinou]

Closing in favor of godotengine/godot-proposals#8146, as feature proposals are tracked on the godot-proposals repository.