ci: 👷 fix "deployment failed" message on main

[mariohamann]

User Story

As a developer of the Solid Design System, I would like to not be irritated from that the deployment on GitHub pages failed, although it worked.

Suggested Solution

On main there's no comment to update, only on PRs. That's why the last step is failing. We should have an if clause that checks, whether we are in a PR or not.

Environment (GitHub Actions or Azure DevOps)

GitHub Actions

Technical Information

DoR

• Item has business value
• Item has been estimated by the team
• Item is clear and well-defined
• Item dependencies have been identified

DoD

• Documentation has been created/updated (if applicable)
• Implementation works successfully on feature branch