Merge pull request godotengine#111325 from TokageItLab/state-default-st

Make StateMachinePlayback set `Start` state as default in constructor

Author: Repiteo

scene/animation/animation_node_state_machine.h

@@ -264,7 +264,7 @@ class AnimationNodeStateMachinePlayback : public Resource {
 	String base_path;
 
 	AnimationNode::NodeTimeInfo current_nti;
-	StringName current;
+	StringName current = SceneStringName(Start);
 	Ref<Curve> current_curve;
 
 	Ref<AnimationNodeStateMachineTransition> group_start_transition;