fix: Use correct file protocol prefixing

[AndreasAlbert]

Motivation

The way we treated protocol prefixes was causing problems on windows

Changes

• Unified and corrected prefix generation

[codecov]

Codecov Report

❌ Patch coverage is 77.77778% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 99.87%. Comparing base (243a7d6) to head (5482837).

Files with missing lines	Patch %	Lines
dataframely/_storage/_fsspec.py	69.23%	4 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##           polars-1.38     #271   +/-   ##
============================================
  Coverage        99.87%   99.87%           
============================================
  Files               53       54    +1     
  Lines             3120     3123    +3     
============================================
+ Hits              3116     3119    +3     
  Misses               4        4           

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