remove sd-validation audit

[brendankenny]

#4359 is the original issue structured data issue.

This audit isn't included in any config, but it's still in the repo and tests are still run for it. #14015 had an issue in Node 18 with some usage of Buffers deep in sd-validation-test -> sd-validation -> jsonld -> http-client -> ky-universal -> node-fetch because of an old version of jsonld dependencies. They've landed the fix but the release isn't quite out yet, so working around it with a resolutions entry for now.

However, if we're not going to ever turn the audit on, should we just remove it? The deps for the audit were moved to devDeps in #12466, maybe it's just time to remove for good now?

[davidlehn]

FYI, jsonld v6.0.0 was released so that particular node-fetch audit issue should be gone.