feat: optimise push controller API calls

[Prithpal-Sooriya]

Explanation

Our new backend change allows us to ditch the "Pull then Push" approach for push notification registration links.
So we can remove 1 query in our enable/disable/update notifications flow.

There are still many more API calls we make (notifications flow talks back and forth between 4/5 services), but at least this is a first step.

References

Changelog

@metamask/notification-services-controller

• REMOVED: the getPushNotificationLinks API call as this is not needed due to backend optimizations.

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've highlighted breaking changes using the "BREAKING" category above as appropriate
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes