Fix flaky most-read spec test
Fix flaky most-read spec test

There's a window each day when the most-read spec test will fail because
yesterday's pageview data isn't populated in RESTBase yet.  Check the
schema against the response for the day before yesterday instead.

Change-Id: I3ed6e99a21707be1b112f0ed4a35a30081a03f02

wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps,wikimedia/mediawiki-services-mobileapps