AnimationTrackEditor Fix signal connection on root exiting the tree

(cherry picked from commit 2ede2bac0bb14b96b0d6f65e99d4eeccdc00702b)

editor/animation_track_editor.cpp

@@ -3201,7 +3201,7 @@ Ref<Animation> AnimationTrackEditor::get_current_animation() const {
 	return animation;
 }
 
-void AnimationTrackEditor::_root_removed(Node *p_root) {
+void AnimationTrackEditor::_root_removed() {
 	root = nullptr;
 }
 

editor/animation_track_editor.h

@@ -371,7 +371,7 @@ class AnimationTrackEditor : public VBoxContainer {
 	TrackIndices _confirm_insert(InsertData p_id, TrackIndices p_next_tracks, bool p_create_reset, Ref<Animation> p_reset_anim, bool p_create_beziers);
 	void _insert_delay(bool p_create_reset, bool p_create_beziers);
 
-	void _root_removed(Node *p_root);
+	void _root_removed();
 
 	PropertyInfo _find_hint_for_track(int p_idx, NodePath &r_base_path, Variant *r_current_val = nullptr);