Month views with two instances of the same month day number highlight both as 'today'.

Summary: Fixes T8334, Month views with two instances of the same month day number highlight both as 'today'.

Test Plan: Open May, only today 27th should be highlighted

Reviewers: epriestley, #blessed_reviewers

Reviewed By: epriestley, #blessed_reviewers

Subscribers: Korvin, epriestley

Maniphest Tasks: T8334

Differential Revision: https://secure.phabricator.com/D13044