TransformControls: Fix `dispose()`. (#29512)

examples/jsm/controls/TransformControls.js

@@ -536,12 +536,7 @@ class TransformControls extends Controls {
 
 		this.disconnect();
 
-		this.traverse( function ( child ) {
-
-			if ( child.geometry ) child.geometry.dispose();
-			if ( child.material ) child.material.dispose();
-
-		} );
+		this._root.dispose();
 
 	}
 
@@ -811,6 +806,17 @@ class TransformControlsRoot extends Object3D {
 
 	}
 
+	dispose() {
+
+		this.traverse( function ( child ) {
+
+			if ( child.geometry ) child.geometry.dispose();
+			if ( child.material ) child.material.dispose();
+
+		} );
+
+	}
+
 }
 
 class TransformControlsGizmo extends Object3D {