Remove IVW tracking code from backend URLs

Currently it is not related to any IVW block config in backend anymore, because hook_page_attachments() also adds preload link to HTML header and this results in warning on backend URLs like node/add/article and so on.

To avoid these warning of non-requested JS files which got added as preload links it would be good to avoid attaching them to admin theme handled URLs.

Attached screenshot of console errors you will get on node/add/article form.

lgtm

Merged, thank you!

Automatically closed - issue fixed for 2 weeks with no activity.