$root_parent not as optional as declared

I’ve addressed the TypeError in ParagraphEditForm::save() by adding a check for $this->rootParent before calling shouldCreateNewRevision().

Since the missing rootParent seems to be caused by a bug in the All Entity Preview module, I opted for a middle-ground approach:

If rootParent is missing, a warning is logged to help with debugging.
The form still triggers a save—defaulting to creating a new revision— to prevent potential data loss.
I didn’t use a hard error (like throwing an exception) to avoid breaking content workflows. Let me know if you'd prefer stricter error handling or further adjustments!

The changes look good to me. Installed the module and did some manual testing. Working as expected with no errors.

@bbrala Please check the recent changes and merge.

Strict Parameter Enforcement

// In ParagraphEditForm.php
public function buildForm(array $form, FormStateInterface $form_state, ?EntityInterface $root_parent = NULL) {
  if (!$root_parent) {
    throw new \InvalidArgumentException('The root parent entity must be provided.');
  }
  // Rest of the method
}