app crash by importing a private key without an email address

[martgil]

Description:
I have found an issue with the latest version of FlowCrypt app 1.2.4 that crashes the Keys view after importing a private key that doesn't contain an email.

Tested from an emulator and a real device.

Steps to reproduce:
crashed.asc.txt

1. Download the crashed.asc.txt file (optional to rename if the app happens to unrecognized the file`
2. Import the private key with the passphrase: passphrase
3. The app will crash after the key is imported successfully.
4. Open the FlowCrypt app once again and go to Keys and the app will crash once again.

Impact:
A user will no longer be able to access the Keys without even uninstalling the app.

[DenBond7]

#1523 will resolve this issue