Upgrade path for full_date data type

Here's a patch for the changes proposed above. This works with both the local elastic search instance and an ElasticCloud instance using the patch here: https://www.drupal.org/project/elasticsearch_connector/issues/3522107#co... ✨ Connect to an Elastic Cloud Hosted Deployment acting as a Search API Server by entering a Cloud ID and API key Active

Thanks for working on this! Now that we have almost 1000 installs on 8.x branch, I'd be a little cautious to add a new update hook. The issue summary suggest adding it to existing one, so it would work for people coming from 8.x-7.x branch. People already on 8.x branch have probably done this by custom module.

Also the new full_date plugin does not have same logic as 8.x-7.x branch (see https://git.drupalcode.org/project/elasticsearch_connector/-/commit/b4f2...).

We should add tests for this feature.

I've removed the hook_update from the install file. See attached.

The patch looks good, but as @sokru pointed out, it needs tests. Automated tests ultimately benefit you (and your client(s)): they ensure future changes will not break the functionality your site depends on.

If you need help writing tests, please ask us!

Updating issue summary

Link to merge request in issue summary.