Fix Playground PR preview

[carstingaxion]

Describe the bug

The last recent PRs didn't had working preview Playgrounds.

1. The first reason was easy found and fixed fast: I needed to update a GitHub token, that I renewed meanwhile. ✔️
2. Now things got strange:
   1. The normal preview link like this, fails
   2. It still shows, that the zip file is loaded from the artifact and installed
   3. But it won't activate automatically
   4. Even I can do that manually without any problems

Steps to Reproduce

..

Screenshots, screen recording, code snippet

Environment information

No response

WordPress information

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[carstingaxion]

• The "pluginZipFile" option of the "installPlugin" step is deprecated. Use "pluginData" instead.
• The "zipPath" option of the unzip() Blueprint step is deprecated and will be removed. Use "zipFile" instead.
• Invalid blueprint: must be object at /steps/6/zipFile

[carstingaxion]

Error: Error when executing the blueprint step #7 ({"step":"installPlugin","pluginData":{"resource":"vfs","path":"/wordpress/pr/gatherpress.zip"},"options":{"activate":true}}) : 
Plugin /wordpress/wp-content/plugins/gatherpress could not be activated – WordPress exited with no error. Sometimes, when $_SERVER or site options are not configured correctly, WordPress exits early with a 301 redirect. Inspect the "debug" logs in the console for more details

[carstingaxion]

Not starting a multisite fixes the issue

Using the Preview link from #949 and just removing:

    {
      "step": "enableMultisite"
    },

... everything is fine.

[carstingaxion]

Moving the enableMultisite step to the end of the blueprint, after the plugin is activated, works, too.

[carstingaxion]

Superstrange.