[iOS] The generated key without back up doesn't marked as the key without back-up after importing

[DmitryBespalov]

Steps:

1. create a new key and skip backup process
2. export the data to the file
3. delete the key from step 1
4. import the file
   Current result: there is lock icon near the keys , but there is no mark near the key in the keys list

[DmitryBespalov]

Technically, the keys are backed up, in the encrypted file. However, this is not the same as backing them up with a seed phrase. For now, I think, we should keep it as is.