Handle export of entity_id for group relationships

Problem/Motivation

When using the export api in core the entity_id field is exported as a numeric id. When importing back the entities referenced don't have the same numeric id. The rest of the fields export fine with an UUID.

Steps to reproduce

Create some group relationships and export with the following command:
dr content:export --with-dependencies --dir=../recipes/default_content/content group_relationship

"default_content" being the name of my recipe.

Proposed resolution

Handle the special case of that field.

Remaining tasks

Code

User interface changes

None

API changes

None

Data model changes

None