style: enable StaticVariableName in checkstyle

[vaibhav9t1]

Related to #5119

• 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

Attention: Patch coverage is 58.33333% with 15 lines in your changes are missing coverage. Please review.

Project coverage is 38.56%. Comparing base (1607421) to head (9aa8722).

Files	Patch %	Lines
...healgorithms/dynamicprogramming/FordFulkerson.java	0.00%	7 Missing ⚠️
.../main/java/com/thealgorithms/others/RabinKarp.java	0.00%	4 Missing ⚠️
...healgorithms/others/StringMatchFiniteAutomata.java	0.00%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #5173   +/-   ##
=========================================
  Coverage     38.56%   38.56%           
  Complexity     2378     2378           
=========================================
  Files           516      516           
  Lines         15313    15313           
  Branches       2957     2957           
=========================================
  Hits           5906     5906           
  Misses         9121     9121           
  Partials        286      286           

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