fix(assets): use PhpAsset::load()

closes #2660

app/setup.php

@@ -32,7 +32,7 @@ add_action('wp_enqueue_scripts', function () {
  * @return void
  */
 add_action('enqueue_block_editor_assets', function () {
-    if ($manifest = asset('scripts/manifest.asset.php')->get()) {
+    if ($manifest = asset('scripts/manifest.asset.php')->load()) {
         wp_enqueue_script('sage/vendor.js', asset('scripts/vendor.js')->uri(), ...array_values($manifest));
         wp_enqueue_script('sage/editor.js', asset('scripts/editor.js')->uri(), ['sage/vendor.js'], null, true);