Refine Backup Behaviour

[kugel3]

Description

Pursuant to this discussion, the restore from backup behaviour is fixed and refined by this PR:

1. If you restore a profile from disk which has iCloud sync turned off, we will no longer try to claim it on iCloud (bugfix)
2. If you restore a profile that has iCloud sync turned on and claiming on iCloud fails, we will continue to import (bugfix) but Security Center will show a problem
3. Prior to this, when loading the list of iCloud backups (or migrating keychain backups ahead of loading the list), if something goes wrong we now distinguish between three cases:

• Not logged in to iCloud, show "Not logged in to iCloud" in the list
• No internet, show "Network unavailable" in the list
• Other error (very rare), show "Could not load backups" in the list and the error in an alert

The strings were added here

How to test

(Using Pre-alpha 1.6.1 (1) for now, until this is merged)

1. Try to restore from a file that has iCloud sync disabled
2. Try to restore from a file while internet is off
3. Try to load the list of backups with internet off
4. Try to load the list of backups while logged out of iCloud
5. Try to load the list of backups with iCloud for Radix Wallet disabled

[CyonAlexRDX]

LGTM, suggested some name changes