Preview page templates doesn't work via Liferay Fragments Toolkit

• Type: Impedibug
• Status: Closed
• Priority: Minor
• Resolution: Completed
• Affects Version/s: None
• Fix Version/s: Master
• Component/s: Fragments Toolkit
• Labels: None
• Git Pull Request: https://github.com/liferay/generator-liferay-fragments/pull/126

Step to reproduce:

1. Run yo liferay-fragments in repo to create a new project
2. Access to new project
3. Run npm run add-page-template
4. Run npm run preview
5. Acess to http://localhost:8081

Expected Results:
This is a page template should be shown and the content page template name should be shown in Page Template field.

Actual Results:
The content of preview is empty and the Page Template field is missing. Additionally, The master page template has the same issue.

Reproduced on:
Tomcat 9.0.33 + MySQL 5.7. Portal master GIT ID: cbe13b3d9c2b7ffa0e5c173f70e2914bb25f55b7.