SSv4: DB table name changed from EmbeddedObject to LinkableEmbed

[micschk]

Not sure if there's a reason for changing the db table name for EmbeddedObject(?)
But currently when updating from Silverstripe 3 to 4, all EmbeddedObjects disappear due to the database table having changed between 3 & 4.

Quick fix is to revert the table name back to the previous value from config.yml:

Sheadawson\Linkable\Models\EmbeddedObject:
  table_name: 'EmbeddedObject'