Resolve @todo comments in \Drupal\Tests\layout_builder\FunctionalJavascript\LayoutBuilderTest

Problem/Motivation

There are a few @todo comments in LayoutBuilderTest:

@todo Remove in https://www.drupal.org/project/drupal/issues/2909782.

But 📌 Provide the ability for JS functional tests to track whether the page has been reloaded Closed: outdated was closed outdated with no explanation.

Steps to reproduce

$ grep "@todo" core/modules/layout_builder/tests/src/FunctionalJavascript/LayoutBuilderTest.php 
   * @todo Remove in https://www.drupal.org/project/drupal/issues/2909782.
   * @todo Remove this in https://www.drupal.org/project/drupal/issues/2918718.
   * @todo Remove in https://www.drupal.org/project/drupal/issues/2909782.
   * @todo Remove in https://www.drupal.org/project/drupal/issues/2909782.

Proposed resolution

TBD

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet