Make Android Authentication sign-in more robust in low-connectivity environments.

[andrewtremblay]

Less urgent since we'll be migrating to the signin-less authentication of Version 3 very soon. Might close this issue due to the deprecation.

On bad connection we get a default page timeout in the webview. Clicking the link in the webview triggers a reload which prompts another page to be added to the webview stack. On successful sign in you then are stuck in the sign in webpage.

Repro:
• Enable airplane mode.
• Open an app with authentication.
• Click the 404 link once or a couple times.
• Disable airplane mode.
• Open app, reload.
• Sign in. Success. You're stuck on the sign in page.