Implement a function to compute the nth Catalan number

[UTSAVS26]

• 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

All modified and coverable lines are covered by tests ✅

Project coverage is 70.44%. Comparing base (70adf6f) to head (931f9de).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5846      +/-   ##
============================================
+ Coverage     70.42%   70.44%   +0.01%     
- Complexity     4794     4800       +6     
============================================
  Files           641      642       +1     
  Lines         17390    17399       +9     
  Branches       3346     3347       +1     
============================================
+ Hits          12247    12256       +9     
  Misses         4681     4681              
  Partials        462      462              

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[UTSAVS26]

@saahil-mahato changes made as per requested, thank you for your time.

[UTSAVS26]

@alxkm please review my PR.

[siriak]

Looks good, thanks!