Inherit title and description from metadata into social cards (#57857)
Social metadata will be display properly if there's `title` and `description` configured.
If you have `title` and `description` configured in metadata, some people's intuition will be "yes I had them, they should be the same if I have `openGraph` or `twitter`".
This PR improves the configuration that you don't have to configure them as duplicate both in top `metadata` export and `metadata.openGraph` or `metadata.twitter`. But we don't always assign them if you don't configure social cards (open graph or twitter), this way users should be able to omit social cards if possible.
x-ref: [feedback from slack](https://vercel.slack.com/archives/C03KAR5DCKC/p1698548491415089?thread_ts=1698512393.500649&cid=C03KAR5DCKC)