Support replicate functionality

When trying to replicate a simple node with 2 paragraphs using the paragraphs_asymmetric_translation_widgets, I get the following error:
AssertionError: Cannot load the "paragraph" entity with NULL ID. in assert() (line 295 of core/lib/Drupal/Core/Entity/EntityStorageBase.php).

It is fixable by editing
paragraphs_asymmetric_translation_widgets/src/EventSubscriber/ReplicateAsymmetricParagraphsSubscriber.php

And adding:

          // Validate target_id before trying to replicate the ite.
          if (!isset($item['target_id']) || is_null($item['target_id'])) {
            continue;
          }

After line 75

Trying to add this on top of patch #4

Just one more confirmation that the patch yields the expected results.
Before: replicas shared paragrahs in non-default translations
After: replicas create new clones of paragraphs for the new replica.

Thanks for the contribution