update LinkEditModal using /_api/v3/page

packages/app/src/components/PageEditor/LinkEditModal.jsx

@@ -162,7 +162,8 @@ class LinkEditModal extends React.PureComponent {
       const pageId = isPermanentLink ? pathWithoutFragment.slice(1) : null;
 
       try {
-        const { page } = await this.props.appContainer.apiGet('/pages.get', { path: pathWithoutFragment, page_id: pageId });
+        const { data } = await this.props.appContainer.apiv3Get('/page', { path: pathWithoutFragment, page_id: pageId });
+        const { page } = data;
         markdown = page.revision.body;
         permalink = page.id;
       }