test: find sigma tests should be multi version

[noa-starkware]

Note

Converts FindSigma* migration flows to MultiVersionFlowTrait (V1,V2) and moves their tests from fork_test.cairo to multi_version_tests.cairo.

• Tests (multi-version):
  • Convert flows to MultiVersionFlowTrait with versions() -> [V1, V2] and unified setup/test(..., version):
    • FindSigmaMigrationFlow
    • FindSigmaEdgeCasesMigrationFlow
    • FindSigmaMigrationIdxIsOneFlow
  • Move corresponding tests from flow_test/fork_test.cairo to flow_test/multi_version_tests.cairo (using test_multi_version_flow_mainnet).

^{Written by Cursor Bugbot for commit ed4305b. This will update automatically on new commits. Configure here.}

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This change is 

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.43%. Comparing base (d05bb77) to head (ed4305b).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #36      +/-   ##
==========================================
- Coverage   95.94%   95.43%   -0.51%     
==========================================
  Files          47       45       -2     
  Lines       11703     9446    -2257     
==========================================
- Hits        11228     9015    -2213     
+ Misses        475      431      -44     

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[NirLevi-starkware]

@NirLevi-starkware reviewed 3 of 3 files at r1, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @noa-starkware)