swift-button-functional-test job failing due to returning user #519

The swift-button-functional-test job appears to no longer pass, due to changes in the web pages of the sign in flow.

One of the web pages have a change in the text. The test is getting "You're signing back in to Days Until Birthday", whereas the text expects "Sign in to Days Until Birthday". This should be updated so that in testSignInNavigateToDaysUntilBirthdayAndDisconnect() will check for the returning user disclaimer header text instead of the previous header text.