TOC not displaying set elements when placed via Layout Builder

Problem/Motivation

Using CkEditor Embedded content or by placing the TOC block, one doesn't see the list of items, from the settings e.g. h2, h3.

Steps to reproduce

Drupal 11.2.4
PHP 8.3
Layout Builder

When one places the block, one gets:

Warning: Undefined array key "#id" in sector_toc_preprocess_block() (line 25 of /var/www/html/public/profiles/contrib/sector/modules/sector_toc/sector_toc.module)

Proposed resolution

Change:

$variables['elements']  to  $variables['elements']["#configuration"]["id"]

Remaining tasks

Check that TOC works with Embedded content, and by placing the block, and via Layout Builder.