Add Search a 2D Matrix algorithm

[AHVSSATHVIK]

Description

This pull request adds the Search a 2D Matrix algorithm to the directory
src/main/java/com/thealgorithms/matrix/.

This algorithm solves the well-known problem where each row of the matrix is sorted,
and the first element of each row is greater than the last element of the previous row.
A binary search is applied on the virtual 1D representation of the matrix to achieve
O(log(m*n)) time complexity.

A detailed explanation of the problem can be found here:
https://leetcode.com/problems/search-a-2d-matrix/

This implementation includes:

• Clean binary search logic
• JavaDoc-style documentation
• Proper placement within the matrix package

Type of Change

• [x] New Algorithm (non-breaking addition)
• [x] Enhancement to the matrix category

Checklist

• [x] I have read CONTRIBUTING.md.
• [x] This pull request is all my own work.
• [x] File name follows PascalCase.
• [x] Function and variable names follow Java coding conventions.
• [x] Added the required URL reference in the JavaDoc comment.
• [x] Code is formatted with clang-format as required.

[codecov-commenter]

Codecov Report

:x: Patch coverage is 0% with 18 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 78.43%. Comparing base (1c6026e) to head (3018106).

Files with missing lines	Patch %	Lines
.../java/com/thealgorithms/matrix/Search2DMatrix.java	0.00%	18 Missing :warning:

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #7114      +/-   ##
============================================
- Coverage     78.50%   78.43%   -0.07%     
+ Complexity     6752     6751       -1     
============================================
  Files           759      760       +1     
  Lines         22402    22420      +18     
  Branches       4400     4403       +3     
============================================
- Hits          17587    17586       -1     
- Misses         4109     4127      +18     
- Partials        706      707       +1     

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[AHVSSATHVIK]

i have made the changes