Cross-device signing is not set up on newly registered account.

On some phones (noticed with Xiaomi), cross-device signing is not set up on a newly created account.
- New DMs are created unencrypted.
- Unable to verify.
- Settings says cross-device signing is not enabled.

This is even worse given that there is no way to set it up from the settings. Only way to set up from Element Android is to log out, and log in, then it pops up the "Upgrade encryption" dialog.
After logging out and in, Element shows the "Riot is now Element" dialog before the "Upgrade encryption" dialog, however, Riot was never installed on that phone, and Element didn't show it when first opened (after installing it, before registration), so maybe it's a database problem.

**To Reproduce**
1. Install Element on Xiaomi phone
2. Register a new account

**Expected behavior**
Cross-device signing is set up on newly registered account.
If it isn't set up, ask the user if they want to open the error report screen.

**Smartphone (please complete the following information):**
- Device: Xiaomi (multiple models, it works on some, but not on others)

**Additional context**
- App version and store: 1.0.9 Play
- Homeserver: grin.hu