Error when first time used and allow field title.

Problem/Motivation

Error generated when I'm trying to use it with LBuilder. I didn't try without LBuilder.

Steps to reproduce

Create Content Type
Add field entity reference
Add field into view modes with Layout Builder.
Use formatter entity_bs_accordion_tab_formatter

Then I get the error Drupal\entity_bs_accordion_tab_formatter\Plugin\Field\FieldFormatter\EntityBSAccordionTabFormatter->settingsForm() .

Proposed resolution

Check the variable before use it.

Allow the possibility to use title node as title accordion/tab.