Add input validation and clarify sorted array requirement in Binary Search

[SwaatiR]

This PR adds a null and empty input check to the Binary Search implementation
to prevent invalid access and improves the JavaDoc to clearly state that the
algorithm requires a sorted array.

No changes were made to the core algorithm logic.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 50.00000% with 1 line in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (master@fd0bcb7). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
.../java/com/thealgorithms/searches/BinarySearch.java	50.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             master    #7216   +/-   ##
=========================================
  Coverage          ?   79.05%           
  Complexity        ?     6945           
=========================================
  Files             ?      779           
  Lines             ?    22908           
  Branches          ?     4502           
=========================================
  Hits              ?    18109           
  Misses            ?     4077           
  Partials          ?      722           

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