fix: constant inputs in LongestIncreasingSubsequence::findLISLen

[vil02]

This PR adds missing tests, fixes LongestIncreasingSubsequence::findLISLen to handle constant and empty inputs and removes the main method from LongestIncreasingSubsequence.

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• 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.
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[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 38.57%. Comparing base (0f42e99) to head (ec10f94).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #5160      +/-   ##
============================================
+ Coverage     38.27%   38.57%   +0.30%     
- Complexity     2362     2377      +15     
============================================
  Files           516      516              
  Lines         15322    15315       -7     
  Branches       2957     2957              
============================================
+ Hits           5864     5908      +44     
+ Misses         9173     9121      -52     
- Partials        285      286       +1     

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