fix: Prevent null array offset errors in Provider.php for ORCID

[gmeben]

In the event user data in the response from ORCID does not have a supplied name, an "array offset" error will be encountered because the value key won't exist as it's currently specified.

"Family names" (or last names) are considered optional by ORCID, which means $user['person']['name']['family-name'] won't always have a ['value'] key available.

For the moment, "given names" (or first names) are required by ORCID so there's no problem assuming this ['value'] information will exist in the response, but if ORCID ever does the right thing and makes "given names" optional, this will cause errors. It would be a good idea to future proof this with a null coalesce as well. My solution also reduces code duplication.