Exclude Premium users from seeing new tab campaigns

Background / User story

ABP Premium is out in the wild and is starting to get attention. Considering we're having more frequent communication with our users, we need to ensure our paying subscribers aren't targeted in "upgrade" type of notifications (bubble UI, new tab, etc.).

What to change

Introduce the ability to show notifications to users depending on their subscription status (free or premium). As a first minimum step, we should at least be able to exclude Premium users from receiving notifications that prompt them to upgrade.

• Design: N/A
• Research: N/A
• Spec: https://gitlab.com/adblockinc/ext/adblockplus/spec/-/merge_requests/410
• Legal: N/A
• Development: Apply the same behavior as for "newtab" notifications that don't include any URLs to open.

Hints for testers

"newtab" notifications that are ignored (either because the user has an active Premium license, or because the notification doesn't include any URLs to open) should not block subsequent notifications from being shown.

Hints for translators

N/A