[Jetpack Content Migration Flow] Improve error handling when migration fails for JP -> WP flow

[twstokes]

Expected behavior

Better handling of the error, perhaps showing an error message.

Actual behavior

The "Welcome to Jetpack!" view is shown again after transitioning from Jetpack to WordPress and back to Jetpack.

Video courtesy of @salimbraksa.

export-failure.mp4

Steps to reproduce the behavior

1. Clean install the WordPress app (21.3) and authenticate.
2. Disconnect from the Internet and add an unsynced local draft to simulate a content export failure.
3. Clean install the Jetpack app and load it.
4. Expect: UI to be shown explaining to the user they can open WordPress.
5. Tap "Open WordPress".

Tested on iPhone 12 Pro, iOS 16, WPiOS 21.3

[twstokes]

More discussion here.

[dangermattic]

Thanks for reporting! 👍