IOS app is falsely claiming signage

[Plosie]

Describe the bug:
When using a third-party (open standard) PGP client to send encrypted (not signed) mail to a Protonmail address, using the corresponding Protonmail public key for encryption; The IOS app on the receiving end will claim "PGP-encrypted and signed message" even though the message is only encrypted and not signed.

This claim is made in the little encryption status icon (green padlock) in the "From" field.

In the webapp the icon will correctly claim "PGP-encrypted message"

Live App Version:
4.0.7

Device + OS version
iPhone 11 iOS 16.

Can you reproduce the problem each time?
Yes

Steps to reproduce the behavior:

1. Set up third party PGP client and import a Protonmail public key
2. Send mail to address using corresponding Protonmail public key. Do encrypt message, do NOT sign message.
3. The IOS app will claim both encrypted and signed.

Expected behavior
The IOS app should claim "Encrypted", "Signed" or "Encrypted and Signed" depending on the situation, as is the case in the webapp.