Add query for 404 page via settings

Author: ravewebdev

api/wordpress/pages/queryError404Page.js

@@ -0,0 +1,20 @@
+import {gql} from '@apollo/client'
+import {singlePageFragment} from './queryPageById'
+
+// Query: retrieve 404 error page.
+const queryError404Page = gql`
+  query GET_ERROR_404_PAGE($imageSize: MediaItemSizeEnum = LARGE) {
+    additionalSettings {
+      additionalSettings {
+        error404Page {
+          ... on Page {
+            ...SinglePageFields
+          }
+        }
+      }
+    }
+  }
+  ${singlePageFragment}
+`
+
+export default queryError404Page