Cleanup workflow from un-thought code

[carstingaxion]

Description of the Change

Revert additional step from the Playground preview workflow, that was meant to restrict the workflow runs to the only necessary ones. Now the workflow is back to its former overall-strategy that triggers on every change to:

• 'build/**'
• 'includes/**'
• 'src/**'
• '*.php'

Thanks to @mauteri for helping out on this via slack.

Closes # Testing & Clean-up after #666, #741, #749, #750, #753 & #757

How to test the Change

1. Test that it NOT runs
   
   1. Open a PR
   2. ...with changes to `.github/...` or `.wordpress-org/...`
   3. See that the whole workflow is NOT triggered.

2. Test that it updates the comment 
   
   1. In one of the opened PRs
   2. ... do some changes
   3. See that the `build` step runs succesfully & the comment is updated.

Changelog Entry

Fixed Run-Trigger for the Playground PR preview

Credits

Props @carstingaxion, @mauteri

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[what-the-diff]

PR Summary

• Deletion of the "needs-build" task from the workflow
  • This modification involves the removal of a previously existing task (named "needs-build") from our workflow process. It means that this particular job or task is no longer necessary in our overall operation.
• Removal of the conditions checking for the presence of a "needs-build" task in the "zip" task
  • This update removes the verification process that checks for the "needs-build" task within the "zip" task. Essentially, the "zip" task no longer depends on the existence of the "needs-build" task.
• Elimination of the conditions checking for the presence of a "needs-build" task in the "comment" task
  • Similarly, the condition checking for the "needs-build" task in the "comment" task is also removed, making the "comment" task more independent.
• Removal of conditional execution in the "comment" task
  • Finally, the "comment" task is now always operational, irrespective of any conditions. It implies that irrespective of any situation, the "comment" task would always execute.