This screen needs to be updated in a couple of ways:

1. We should display it in the same navigator as the rest of the flow. This improves consistency.
2. A cancel button should be removed, because we don't support restoring an account without restoring the backup.
3. A loading state should be added to the SIWE button.
4. Some minor layout tweaks are necessary for the screen to look consistent.

https://linear.app/comm/issue/ENG-9967/connect-the-siwe-logic-with-the-ui

Depends on D14163

Tested in combination with the rest of the stack. Made sure the screen looks good and can be used.