Missing details in OAuth2ClientProperties validation error message #42278
Description
Method of validation use only client id, but if you have a large and complex configuration, collected from various sources, it is difficult to understand exactly where something went wrong.
For example, our configuration stores client-id in one place and client-secret in another. If I delete the client-id and forget to delete the client-secret, I will receive an error message like Caused by: java.lang.IllegalStateException: Client id must not be empty.. But from this message it is unclear in which particular registration went wrong.
This line actually contains the names of registration (they are stored as keys in the Map), I suggest using them.