Refactor Comments Examples

[InosRahul]

Refactored playground examples which are present here: https://github.com/PSPDFKit/awesome-nutrient/blob/master/playground/web-comments.md

• Set annotation creator name

• Clean up empty comment threads and highlights

  • Prevent stray comment markers when someone opens a thread but no longer wants it. If no real text is entered and no comments are posted, the yellow highlight/marker is auto-removed when the editor closes, keeping pages tidy. Press Escape to instantly clear temporary markers while drafting

[miguelcalderon]

LGTM, reviewed and tested 👍