fix: fields and curves fuzzers fix

[entropidelic]

This PR fixes fuzzers from the no_gpu_fuzz modules: fields and curves.

The pairing operation in the bn254 fuzzer was removed since we don't have a pairing implementation there yet

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 72.28%. Comparing base (1a6d14e) to head (8276b10).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #861   +/-   ##
=======================================
  Coverage   72.28%   72.28%           
=======================================
  Files         149      149           
  Lines       33823    33823           
=======================================
  Hits        24450    24450           
  Misses       9373     9373           

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