Migrated the IntroScreen to use DataStore instead of SharedPreferences.

[MohitMaliFtechiz]

Fixes #4517

Parent PR #4516

Continuing from #4516

• Migrated the IntroScreen functionality to use DataStore.
• Refactored all related UI test cases to use DataStore instead of SharedPreferences.
• Added a migration test case to verify the transfer of data from SharedPreferences to DataStore.

[codecov]

Codecov Report

❌ Patch coverage is 80.95238% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 59.01%. Comparing base (30402b9) to head (e3fa136).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...kiwixmobile/core/utils/datastore/KiwixDataStore.kt	71.42%	1 Missing and 1 partial ⚠️
...va/org/kiwix/kiwixmobile/main/KiwixMainActivity.kt	0.00%	0 Missing and 1 partial ⚠️
...va/org/kiwix/kiwixmobile/core/base/BaseActivity.kt	50.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #4518      +/-   ##
============================================
+ Coverage     58.92%   59.01%   +0.09%     
- Complexity     1534     1541       +7     
============================================
  Files           327      327              
  Lines         17627    17640      +13     
  Branches       2185     2185              
============================================
+ Hits          10386    10411      +25     
+ Misses         5805     5796       -9     
+ Partials       1436     1433       -3     

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[kelson42]

@MohitMaliFtechiz Can you please rebase and fix conflicts?

[MohitMaliFtechiz]

@kelson42 Conflicts are resolved.