Add Sudoku solver using backtracking with tests

[prasanth-30011]

• [ ] I have read CONTRIBUTING.md.
• [ ] This pull request is all my own work -- I have not plagiarized it.
• [ ] All filenames are in PascalCase.
• [ ] All functions and variable names follow Java naming conventions.
• [ ] All new algorithms have a URL in their comments that points to Wikipedia or other similar explanations.
• [ ] All new code is formatted with clang-format -i --style=file path/to/your/file.java

[codecov-commenter]

Codecov Report

:white_check_mark: All modified and coverable lines are covered by tests. :white_check_mark: Project coverage is 78.48%. Comparing base (e6c576c) to head (768b5a2).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #7087      +/-   ##
============================================
+ Coverage     78.46%   78.48%   +0.02%     
+ Complexity     6746     6739       -7     
============================================
  Files           758      758              
  Lines         22339    22324      -15     
  Branches       4384     4380       -4     
============================================
- Hits          17528    17522       -6     
+ Misses         4107     4098       -9     
  Partials        704      704              

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[github-actions[bot]]

This pull request has been automatically closed because its workflows or checks failed and it has been inactive for more than 14 days. Please fix the workflows and reopen if you'd like to continue. Merging from main/master alone does not count as activity.