fix: E2EI flow can be interrupted - WPB-23171 🍒

[github-actions]

This PR was automatically cherry-picked based on the following PR:

• fix: E2EI flow can be interrupted - WPB-23171 #4363

Original PR description:

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WPB-23171 [iOS] E2EI enrollment flow is interrupted

Issue

When logging in to an account that requires End-To-End-Identity, if the user interrupts the E2EI enrollment flow (either put app in BG then FG, or restart app) then the user can bypass the flow and end up in a state where they should have E2EI but don't and can't get it.

The logic to determine what is the top level app state (e.g authenticated -> go to conversation list, or e2ei required -> go to e2ei flow) is spread out in various places and is a fragile network of competing code paths. This broke at some point due to the various refactoring made to session loading and authentication flows.

The solution was to go step by step correcting various regressions, which I won't explain here but instead via comments on the changes.

Testing

There are three main flows to test:

1. Log in to an account that requires E2EI without interruption (log in -> conversation list), verify success.
2. Log in to an account that requires E2EI, but before completion go BG, then FG, complete and verify success.
3. Log in to an account that requires E2EI, but before completion terminate app. Relaunch, see E2EI flow, complete and verify success.

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Checklist

• Title contains a reference JIRA issue number like [WPB-XXX].
• Description is filled and free of optional paragraphs.
• Adds/updates automated tests.

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UI accessibility checklist

If your PR includes UI changes, please utilize this checklist:

• Make sure you use the API for UI elements that support large fonts.
• All colors are taken from WireDesign.ColorTheme or constructed using WireDesign.BaseColorPalette.
• New UI elements have Accessibility strings for VoiceOver.

[sonarqubecloud]

Quality Gate passed

Issues
5 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
2.5% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Test Results

6 295 tests   6 268 ✅  8m 15s ⏱️
  782 suites     27 💤
    4 files        0 ❌

Results for commit 8608599.

Summary: workflow run #22712075129
Allure report (download zip): html-report-28311-fix_e2ei-interruption-wpb-23171-cherry-pick

[zenkins]

✅ Auto-approved cherry-pick PR 🍒.