fix(schema-org): nuxt test utils compat bug

Author: harlan-zw

packages/schema-org/src/plugin.ts

@@ -176,7 +176,7 @@ export function SchemaOrgUnheadPlugin(config: MetaInput, meta: () => Partial<Met
           let firstNodeKey: number | undefined
           for (const k in ctx.tags) {
             const tag = ctx.tags[k]
-            if (!tag)
+            if (!tag?.props)
               continue
             if ((tag.props.type === 'application/ld+json' && tag.props.nodes) || tag.key === 'schema-org-graph') {
               delete tag.props.nodes