Clear Fund initiative notifications when viewing an initaitive

Summary: Fixes T6301. Just missed this in building out the page.

Test Plan: Viewed an initiative, verified `pageObjects` populated correctly.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T6301

Differential Revision: https://secure.phabricator.com/D10700