Fix/neg factorial

[Tabaie]

Description

leastauthority pointed out that the sumcheck package incorrectly yields negFactorial(1) = 1 (should be -1)
This PR puts the correct implementation from the polynomial package in internal to be used by both.

Update:
The incorrect version of negFactorial was used by InterpolateInRange which itself wasn't used anywhere. negFactorial is back in polynomial.go and InterpolateInRange is deleted.

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

Tests

• TestNegFactorial

Checklist:

• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• I did not modify files generated from templates
• golangci-lint does not output errors locally
• New and existing unit tests pass locally with my changes