Add GCD implementation using Euclidean algorithm

[Swati89923]

Added a GCD implementation using the Euclidean algorithm along with unit tests.

• 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 similar explanations.
• All new algorithms include a corresponding test class that validates their functionality.
• All new code is formatted according to the project standards.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 78.92%. Comparing base (e945f16) to head (132dbd6).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #7189      +/-   ##
============================================
+ Coverage     78.91%   78.92%   +0.01%     
- Complexity     6883     6886       +3     
============================================
  Files           774      775       +1     
  Lines         22746    22758      +12     
  Branches       4468     4471       +3     
============================================
+ Hits          17949    17962      +13     
+ Misses         4077     4076       -1     
  Partials        720      720              

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[Swati89923]

Hi maintainers 👋
Just checking in. Please let me know if any changes are needed from my side.
Thanks!

[Swati89923]

Hi maintainers 👋
Just checking in. Please let me know if any changes are needed from my side.
Thanks!

[DenizAltunkapan]

@Swati89923 whats the difference between your implementation and https://github.com/TheAlgorithms/Java/blob/master/src/main/java/com/thealgorithms/maths/GCD.java ?

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contribution!

[github-actions]

Please reopen this pull request once you have made the required changes. If you need help, feel free to ask in our Discord server or ping one of the maintainers here. Thank you for your contribution!