Chore: Create Sudoku functional test that detects if unsolvable puzzle is attempted

[a2937]

Checklist:

• [X] I have read freeCodeCamp's contribution guidelines.
• [X] My pull request has a descriptive title (not a vague title like Update index.md)

Closes #XXXXX

This was the test that I mentioned in the Sudoku Solver PR that was merged in today.

[gikf]

Note: adding new test will require changing number of expected tests on https://github.com/freeCodeCamp/freeCodeCamp/blob/main/curriculum/challenges/english/06-quality-assurance/quality-assurance-projects/sudoku-solver.md