### Godot version

v4.1.rc2.official [46424488e]

### System information

Godot v4.1.rc2 - Linux Mint 20 (Ulyana) - Vulkan (Forward+) - dedicated NVIDIA GeForce RTX 2060 SUPER (nvidia; 515.105.01) - Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz (8 Threads)

### Issue description

Dragging and dropping a file to a new position inside its current folder, or onto the icon for its current folder - when that folder is the project root folder :res// - will be treated as though you were dropping a different file with the same name.

Expectation: for nothing to happen.

Also tried it in 4.0.3 and 4.1-dev3, where it behaves as expected.

https://github.com/godotengine/godot/assets/64640811/90de1120-dd92-41b8-b202-db77c343103a

### Steps to reproduce

1. New or existing project.
2. Click and drag a file in :res// in FileSystem dock.
3. Drop the file back into :res//.
4. Be prompted to overwrite or rename.

### Minimal reproduction project

N/A
switch (get_icon_mode()) {
		case ItemList::ICON_MODE_LEFT:
			rect = get_item_rect(s, true);
			ofs = Vector2(0, Math::floor((MAX(line_editor->get_minimum_size().height, rect.size.height) - rect.size.height) / 2));
			popup_rect.position = get_screen_position() + rect.position - ofs;
			popup_rect.size = rect.size;
			
			popup_rect.size.x -= icon_size.x;
			popup_rect.position.x += icon_size.x;
			break;
		case ItemList::ICON_MODE_TOP:
			rect = get_item_rect(s, false);
			popup_rect.position = get_screen_position() + rect.position;
			popup_rect.size = rect.size;
			
			popup_rect.size.y -= icon_size.y;
			popup_rect.position.y += icon_size.y;
			break;
	}
	popup_editor->set_position(popup_rect.position);
	popup_editor->set_size(popup_rect.size);
	String name = get_item_text(s);
	line_editor->set_text(name);
	line_editor->select(0, name.rfind("."));
	popup_editor->popup();
	popup_editor->child_controls_changed();
	line_editor->grab_focus();
	return true;
}
String FileSystemList::get_edit_text() {