feat: [IOPLT-1555] Properly handles app language selection and persistence

[CrisTofani]

Short description

This pull request refactors and simplifies the language and locale selection logic in the application streamlining related state management. It also cleans up unused saga code related to language preference synchronization and sets a default preferred language. The changes focus on improving maintainability and user experience for language selection in the preferences screen.

List of changes proposed in this pull request

• Changes on the Language Selection screen
• Removes Saga handler that update local language selection from saved profile language
• split up the logical handle and preferences save

How to test

Change the selected language on Preferences > Preferred Language screen

Simulator.Screen.Recording.-.iPhone.16.Pro.-.2026-03-02.at.15.58.01.mov

[github-actions]

Jira Pull Request Link

This Pull Request refers to Jira issues:

• IOPLT-1555

[github-actions]

PR Title Validation for conventional commit type

✅ All good! PR title follows the conventional commit type.

[codecov]

Codecov Report

❌ Patch coverage is 54.54545% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.04%. Comparing base (d8da09a) to head (7d33270).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
...preferences/screens/LanguagesPreferencesScreen.tsx	50.00%	14 Missing ⚠️
ts/components/ui/IOScrollViewWithLargeHeader.tsx	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #7817      +/-   ##
==========================================
+ Coverage   60.02%   60.04%   +0.02%     
==========================================
  Files        1966     1966              
  Lines       43860    43844      -16     
  Branches    10144    10061      -83     
==========================================
+ Hits        26326    26327       +1     
+ Misses      17446    17438       -8     
+ Partials       88       79       -9     

Files with missing lines	Coverage Δ
ts/config.ts	98.70% <ø> (-0.02%)	⬇️
ts/i18n.ts	100.00% <ø> (ø)
ts/sagas/preferences.ts	0.00% <ø> (ø)
ts/sagas/startup.ts	38.70% <ø> (+0.97%)	⬆️
ts/store/actions/persistedPreferences.ts	100.00% <ø> (ø)
ts/store/reducers/persistedPreferences.ts	72.58% <ø> (ø)
ts/components/ui/IOScrollViewWithLargeHeader.tsx	92.30% <80.00%> (-1.81%)	⬇️
...preferences/screens/LanguagesPreferencesScreen.tsx	58.46% <50.00%> (+1.31%)	⬆️

... and 11 files with indirect coverage changes

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[dmnplb]

Just fixed some wrong (or missing) translations in the de and en locales, then added a logic to display the locales in the following order, according to the design specs:

• it, en (pinned)
• the other ones sorted alphabetically

In my opinion, we can release the new screen without hesitation ✌🏻

[LeleDallas]

We can omit some unnecessary assertions

[CrisTofani]

We can omit some unnecessary assertions

@LeleDallas All addressed in 9c35d21