Jetpack: Can't install Jetpack when self-hosted password is changed

Expected behavior

I expect that the manual installation flow implemented in https://github.com/wordpress-mobile/WordPress-Android/pull/8426 will allow me to manually install Jetpack if the remote install fails because of invalid credentials.

Actual behavior

If I change my self-hosted account password after adding the site to the app, the Jetpack install fails and I end up on a blank screen where I can't proceed.

Steps to reproduce the behavior

1. Set up a self-hosted site without Jetpack.
2. Add the self-hosted site to the app.
3. Change the account password on the self-hosted site (in the web dashboard).
4. In the app, go to Stats.
5. Select "Install Jetpack."
6. Select "Continue."

Result: I see the "Installing Jetpack" screen, and then a webview loads with the beginning of the web flow for Jetpack install, but it quickly ends up on a blank screen:

Tested on Moto E5 Play, Android 8.1.0, WPAndroid alpha-133

cc @planarvoid

Start with the manual installation flow described in WordPress-Android PR 8426 and reproduce the password-change steps on Android. Trace the flow after selecting “Continue” and compare it with the invalid-credentials case. Done means the flow no longer ends on a blank screen and allows manual Jetpack installation when remote installation fails.