$fieldDefinition is null in CommentDeleteManager

The field definition should never be null so this patch is not correct. Take a look at the lines immediately before your changes (shown below). If the comment entity doesn't have a field something in your sites entity or configuration is broken.

    $commentedEntity = $comment->getCommentedEntity();
    /** @var \Drupal\field\FieldConfigInterface $fieldDefinition */
    $fieldDefinition = $commentedEntity->getFieldDefinition($comment->getFieldName());

If you could provide steps to replicate on a fresh installation I will reopen.

robphillips → closed merge request !9

Steps to reproduce:
- In content type we had one comment type - with a "text plain" field
- Some comment entities were created
- We need to change "text plain" to "text field formatted - need CKEditor" that's why we created a new comment type (prev we use in other content types)
- I have removed comment field with plain text and created with formatted
and in the /admin/content/comment found an issue

The website encountered an unexpected error. Please try again later.
Error: Call to a member function getSetting() on null in Drupal\comment_delete\CommentDeleteManager->getConfig() (line 121 of modules/contrib/comment_delete/src/CommentDeleteManager.php).

I know it looks like an exception but It may happen