Fix feed query cursor-based pagination on 32-bit systems

Summary: Fixes T8503. On 32-bit systems, these 64-bit integers will be mangled by the '%d' conversion implied by the 'int' type.

Test Plan: Somewhat guessing here since I don't have a 32-bit system handy, but this strongly echoes similar issues in the past. Feed works fine locally. Looked at the generated queries.

Reviewers: btrahan

Reviewed By: btrahan

Subscribers: epriestley

Maniphest Tasks: T8503

Differential Revision: https://secure.phabricator.com/D13250