Sometimes after migrating to rust crypto, the App requires users to re-verify the device

[BillCarsonFr]

Problem

A session in legacy crypto, which appears verified, is suddenly displaying "verify session" dialogs once migrated to Rust crypto

Explanation

In the legacy crypto the current session is marked as verified (given a valid set of keys, signed as expected):

• If we have the private part of the MSK and it's matching the published public part
• Or the master key is marked as trusted, aka local flag (done at the end of a sucessfull verification)
• Or if the master key is signed by one of our trusted devices

When migrating to rust some of this information is lost. The local trust flag is not migrating, and rust is more conservative and is not considering device signatures.

As a result, sessions that do not have private MSK/USK/SSK (but have either local flag or check valid signature) are migrated over to Rust as untrusted, leading to a "verify your session" dialog, that confuses users.

Proposed Solution

Update the verify dialog text to:
App updated
Secure messaging has been improved with the latest update. Please re-verify your device.

Alternative would be to migrate the local trust flag, but given that some secret are missing a re-verification would be beneficial anyhow.

[BillCarsonFr]

Fixed by #8462