add ability to disable bone flattener in editor

scripts/effects/bone_flattener.gd

@@ -5,6 +5,7 @@ extends Node3D
 @export var skeleton: Skeleton3D
 @export var bones_to_flatten: Array[BoneToFlatten] = []
 @export var mirror_y_angle: float
+@export var editor_preview: bool = false
 
 @export_group("Bone names")
 @export var head_bone_name: String = "Head"
@@ -102,7 +103,7 @@ func _ready() -> void:
 
 
 func _process(_delta: float) -> void:
-	if skeleton == null:
+	if skeleton == null or (Engine.is_editor_hint() and not editor_preview):
 		return
 
 	_get_angle()