Upgrade path for full_date data type

Problem/Motivation

We added pre-epoch date support on 🐛 Handle pre-epoch dates Fixed , however on 8.0.x we don't have full_date data type.

Steps to reproduce

Proposed resolution

Either:
- Add full_date data type to 8.0.x
- Add on existing update hook the task to convert full_date to "string" (see: https://www.drupal.org/project/elasticsearch_connector/issues/3189051#co... 🐛 Handle pre-epoch dates Fixed )

Remaining tasks

User interface changes

API changes

Data model changes