Add a Publish Experience Builder Content permission

wim leers → credited larowlan → .

See #3529207-10: For selective reverting add DELETE auto-save endpoint → , that just landed, and now this MR needs to be updated to also apply the new permission to that new route 🙏

I'll get this done for you :)

This still needed some serious cleaning up. 🙈 Did that.

Created 📌 Expose Publish Experience Builder Content permission to the client UI Active as a follow-up. Expected that to happen here, but I didn't add it to the IS.