Wrong error message in case there are no emails on account

[Kharchevskyi]

Discovered with ui tests and den@flowcrypt.test account.
This account doesn't have any emails on account.

[Kharchevskyi]

@tomholub correct me if i wrong, but in this case we should give user possibility to create backup

[tomholub]

When no emails are present, that means no backups are present. It should not be a special case in any way: backups.count = 0 and then let the code continue to handle it as normally, do whatever it would normally do in that situation.