feat(#272): support ongoing update of user data from claims

[FloppyNotFound]

All Submissions:

• [X] Have you followed the plugin Contributing guideline?
• [X] Does your code follow the WordPress' coding standards?
• [X] Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Changes proposed in this Pull Request:

Support ongoing update of user data from claims. Currently, user data is only synced on first login, if the user does not yet exist in the wordpress database. This PR triggers an update of first name, last name and email on each login.

Closes #272 .

How to test the changes in this Pull Request:

1. Change user data of an existing wordpress user in your OAuth provider
2. Logout
3. Login
4. User data should have changed in Wordpress as well

Other information:

• [X] Have you added an explanation of what your changes do and why you'd like us to include them?
• [ ] Have you written new tests for your changes, as applicable?
• [X] Have you successfully run tests with your changes locally?

Changelog entry

Enter a summary of all changes on this Pull Request. This will appear in the changelog if accepted. Support ongoing update of user data from claims on each login

[timnolte]

@FloppyNotFound there are also checks that are failing that will also need to be addressed.