chore(fraction): make non generic

[RoeeGross]

This change is 

[uriel-starkware]

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @ishay-starkware)

[codecov]

Codecov Report

Attention: Patch coverage is 90.00000% with 1 line in your changes missing coverage. Please review.

Please upload report for BASE (main@5a1ae79). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
src/math/fraction.cairo	90.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #34   +/-   ##
=======================================
  Coverage        ?   87.35%           
=======================================
  Files           ?       36           
  Lines           ?     1289           
  Branches        ?        0           
=======================================
  Hits            ?     1126           
  Misses          ?      163           
  Partials        ?        0           

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