Provide integration with UUID module

Problem/Motivation

In my use case, I have multiple sites that require user uuid to be shared across multiple sites (D7,D8 and D9).
As uuid property can't be changed, setting uuid -> UUID mapping under openid-connect config will lead to this error:

EntityMetadataWrapperException: Entity property uuid doesn't support writing. 

Steps to reproduce

1. Enable SSO between two sites (provider and consumer).
2. Enable uuid module.
3. Go to http://localhost/en/admin/config/services/openid-connect
4. Map user claim 'uuid' to UUID.
5. Login using a new user (allow openid-connect to create a new user in the consumer(client) site)

Proposed resolution

If the uuid module is enable and uuid mapping is configured, allow the uuid to be saved when the user entity is created rather than a later stage where uuid update is not possible.