Improved the scanning of ZIM files in the Play Store variant.

[MohitMaliFtechiz]

Fixes #4148

• Excluded the scanning of other directories in the Play Store variant, as only app-specific directories can be accessed, making it unnecessary to include other directories in the scan.
• Fixed: UI was displaying storage options prematurely while storage information was still being fetched in the background. To resolve this, storage options are initially hidden, and a progress bar with a title is shown to inform users that storage information is being fetched.
  Issue:
  
  Fix:

screen-20241230-155042.mp4

[codecov]

Codecov Report

Attention: Patch coverage is 84.09091% with 14 lines in your changes missing coverage. Please review.

Project coverage is 56.82%. Comparing base (0969102) to head (d94fb5c).
Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
...ixmobile/core/settings/StorageLoadingPreference.kt	83.33%	1 Missing and 10 partials ⚠️
...g/kiwix/kiwixmobile/settings/KiwixPrefsFragment.kt	83.33%	0 Missing and 2 partials ⚠️
...ile/nav/destination/library/CopyMoveFileHandler.kt	0.00%	1 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #4149      +/-   ##
============================================
+ Coverage     56.79%   56.82%   +0.03%     
- Complexity     1515     1519       +4     
============================================
  Files           312      313       +1     
  Lines         13285    13367      +82     
  Branches       1644     1655      +11     
============================================
+ Hits           7545     7596      +51     
- Misses         4609     4637      +28     
- Partials       1131     1134       +3     

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