feat: implement One-Time Pad cipher (#6941)

[newtownboy]

• Added encryption and decryption functions using One-Time Pad
• Included unit tests for edge cases and invalid inputs

• 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 78.34%. Comparing base (2588af0) to head (7e70a9a).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #7022      +/-   ##
============================================
- Coverage     78.35%   78.34%   -0.01%     
- Complexity     6671     6675       +4     
============================================
  Files           753      754       +1     
  Lines         22185    22195      +10     
  Branches       4356     4357       +1     
============================================
+ Hits          17382    17389       +7     
- Misses         4105     4106       +1     
- Partials        698      700       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[github-actions]

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.