Cleanup ftue code and ensure verification confirmation is displayed

[bmarty]

Content

Rework the FTUE code.
Ensure that the verification confirmation screen is displayed.
It could happen that this screen was not displayed in the case of the session verification was the last FTUE step to complete.

It will also help for the multi account feature.

Motivation and context

Code a bit more readable and fix an issue.

Screenshots / GIFs

No expected change

Tests

• Login to an account
• Ensure that all the Ftue steps are displayed and can be completed.

Tested devices

• Physical
• Emulator
• OS version(s):

Checklist

• Changes have been tested on an Android device or Android emulator with API 24
• UI change has been tested on both light and dark themes
• Accessibility has been taken into account. See https://github.com/element-hq/element-x-android/blob/develop/CONTRIBUTING.md#accessibility
• Pull request is based on the develop branch
• Pull request title will be used in the release note, it clearly define what will change for the user
• Pull request includes screenshots or videos if containing UI changes
• You've made a self review of your PR

[github-actions]

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[codecov]

Codecov Report

❌ Patch coverage is 93.33333% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 80.37%. Comparing base (5c893e7) to head (f9d8c9a).
⚠️ Report is 3 commits behind head on develop.

Files with missing lines	Patch %	Lines
...oid/features/ftue/impl/state/DefaultFtueService.kt	92.30%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #5379   +/-   ##
========================================
  Coverage    80.37%   80.37%           
========================================
  Files         2275     2276    +1     
  Lines        62884    62899   +15     
  Branches      7869     7872    +3     
========================================
+ Hits         50542    50555   +13     
- Misses        9436     9437    +1     
- Partials      2906     2907    +1     

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

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

See analysis details on SonarQube Cloud