Reauthentication dialog redirects to self-hosted site settings when disconnecting WP.com account

Steps to reproduce the behavior

1. Log into the app with a WP.com account
2. Log into the app with a non-jetpack connected self-hosted site
3. Make sure your selected site is the self-hosted site
4. Disconnect the app from the WP.com account using https://wordpress.com/me/security/connected-applications
5. Go the the posts screen and back to the home screen
6. Observe a pop-up saying "Connection error: Incorrect username or password" with "Cancel" and "Settings" buttons.
   Tap "Settings"
7. Observe that you are taken to the account settings (i.e., username/password) for the self-hosted site

Expected behavior

This flow made it seem like there was a problem with the self-hosted site instead of the WP.com account that was disconnected. Admittedly this is an edge case though.

Note: these steps were originally provided by @mchowning in pbMoDN-ET-p2#comment-1203

Reproduce the disconnect flow from the posts screen back to the home screen, then inspect the reauthentication dialog and its Settings action. Trace which account is considered disconnected and verify that Settings points to the WP.com account rather than the selected self-hosted site's credentials; repeat the listed steps to confirm the misleading redirect is gone.