Remove polyfill for Node.is_part_of_edited_scene()

We now require Godot 4.3, which introduces this method.

addons/block_code/ui/block_canvas/block_canvas.gd

@@ -67,7 +67,7 @@ signal replace_block_code
 func _ready():
 	_context.changed.connect(_on_context_changed)
 
-	if not _open_scene_button.icon and not Util.node_is_part_of_edited_scene(self):
+	if not _open_scene_button.icon and not self.is_part_of_edited_scene():
 		_open_scene_button.icon = _open_scene_icon
 	if not _zoom_out_button.icon:
 		_zoom_out_button.icon = _icon_zoom_out
@@ -99,7 +99,7 @@ func _can_drop_data(at_position: Vector2, data: Variant) -> bool:
 	# Don't allow dropping BlockCode nodes or nodes that aren't part of the
 	# edited scene.
 	var node := get_tree().root.get_node(abs_path)
-	if node is BlockCode or not Util.node_is_part_of_edited_scene(node):
+	if node is BlockCode or not node.is_part_of_edited_scene():
 		return false
 
 	# Don't allow dropping the BlockCode node's parent as that's already self.

addons/block_code/ui/picker/categories/block_category_button.gd

@@ -16,7 +16,7 @@ func _ready():
 	if not category:
 		category = BlockCategory.new("Example", Color.RED)
 
-	if not Util.node_is_part_of_edited_scene(self):
+	if not self.is_part_of_edited_scene():
 		var new_stylebox: StyleBoxFlat = _panel.get_theme_stylebox("panel").duplicate()
 		new_stylebox.bg_color = category.color
 		_panel.add_theme_stylebox_override("panel", new_stylebox)

addons/block_code/ui/tooltip/tooltip.gd

@@ -27,5 +27,5 @@ func override_fonts():
 
 
 func _ready():
-	if not Util.node_is_part_of_edited_scene(self):
+	if not self.is_part_of_edited_scene():
 		override_fonts()

addons/block_code/ui/util.gd

@@ -1,19 +1,6 @@
 extends Object
 
 
-## Polyfill of Node.is_part_of_edited_scene(), available to GDScript in Godot 4.3+.
-static func node_is_part_of_edited_scene(node: Node) -> bool:
-	if not Engine.is_editor_hint():
-		return false
-
-	var tree := node.get_tree()
-	if not tree or not tree.edited_scene_root:
-		return false
-
-	var edited_scene_parent := tree.edited_scene_root.get_parent()
-	return edited_scene_parent and edited_scene_parent.is_ancestor_of(node)
-
-
 ## Get the path from [param reference] to [param node] within a scene.
 ##
 ## Returns the path from [param reference] to [param node] without referencing