PIN Lock breaks "Open with Reader" flow

[hoverduck]

Steps to reproduce the behavior

1. Set a PIN lock on the WP app
2. Click a link to a post, and select "Open with WordPress.com Reader" if prompted
3. Input PIN

Expected behavior

The post opens in Reader

What actually happens

The post appears extremely briefly before the PIN lock screen opens. After inputting the PIN we're then left on whatever screen was last open in the app.

Note that this works fine if you open the link first in an app's internal browser, then click "Open in Chrome" before being redirected to the Reader.

Tested on Nexus 6P, Android 7.1.1, WP alpha-28

[hypest]

Even though I cannot reproduce this issue, it might get fixed when #4900 gets merged to fix #4887.

[hoverduck]

Closing, no longer able to reproduce