Fix the extra arguments of type `NodePath` in the connection dialog do not work

Make the node path relative to the target node instead of the source node.

Currently, a proxy object is used in the connection dialog to edit bound arguments.

In this case, the `EditorPropertyNodePath` will get the node path relative to the
source object in the connection (i.e. the object the InspectorDock is editing).

This path is not available in scripts (i.e. the target object in the connection).

editor/inspector/editor_properties.cpp

@@ -3069,6 +3069,11 @@ void EditorPropertyNodePath::_notification(int p_what) {
 Node *EditorPropertyNodePath::get_base_node() {
 	Node *base_node = Object::cast_to<Node>(get_edited_object());
 
+	// For proxy objects, specifies the node to which the path is relative.
+	if (!base_node && get_edited_object()->has_meta("__base_node_relative")) {
+		base_node = Object::cast_to<Node>(get_edited_object()->get_meta("__base_node_relative"));
+	}
+
 	if (!base_node) {
 		base_node = Object::cast_to<Node>(InspectorDock::get_inspector_singleton()->get_edited_object());
 	}

editor/scene/connections_dialog.cpp

@@ -113,6 +113,33 @@ public:
 		}
 	}
 
+	void update_base_node_relative(Node *p_node) {
+		Node *old_base = nullptr;
+		if (has_meta("__base_node_relative")) {
+			old_base = Object::cast_to<Node>(get_meta("__base_node_relative"));
+		}
+
+		if (old_base == p_node) {
+			return;
+		}
+		// The cdbinds is a proxy object, so we want the node path to be relative to the target node.
+		set_meta("__base_node_relative", p_node);
+
+		if (!old_base) {
+			return;
+		}
+
+		// Update existing outdated node paths.
+		for (int i = 0; i < params.size(); i++) {
+			if (params[i].get_type() != Variant::NODE_PATH) {
+				continue;
+			}
+			StringName property_name = "bind/argument_" + itos(i + 1);
+			Node *n = old_base->get_node(get(property_name));
+			set(property_name, p_node ? p_node->get_path_to(n) : NodePath());
+		}
+	}
+
 	void notify_changed() {
 		notify_property_list_changed();
 	}
@@ -176,6 +203,9 @@ void ConnectDialog::_tree_node_selected() {
 	if (!edit_mode) {
 		set_dst_method(generate_method_callback_name(source, signal, current));
 	}
+
+	cdbinds->update_base_node_relative(current);
+
 	_update_method_tree();
 	_update_warning_label();
 	_update_ok_enabled();