Trace every request for Notifications Center to Sentry

Summary:
Tracing is useful to watch requests average time.
With only hundreds of events per month at most, we can choose a sample of 100%.

Ref T1791

Test Plan: Browse https://sentry.nasqueron.org/organizations/nasqueron/discover/

Reviewers: dereckson

Reviewed By: dereckson

Maniphest Tasks: T1791

Differential Revision: https://devcentral.nasqueron.org/D2945