Error when submitting encrypted keys for non-private sub-users' aliases

[wussler]

When generating a key for a second or third (and so on) address for a non-private sub-user private key encryption is messed up.

Steps to reproduce:

• Log in as txtspaceblue/12345 on v4.protonmail.blue
• Navigate to the addresses settings panel
• Add an alias (or more) to a non-private sub-user (e.g. daratst2)
• Generate keys (any type is fine)
• Navigate to the users panel
• Click on the little drop down arrow next to it, then login
• Get Incorrect key passphrase error

Important stuff:

• On V3 keys are encrypted correctly
• The error is in the encryption (right after generation), not in the retrieval, in fact the keys are stored wrong on the API.