Added surface area calculation for pyramid

[Hemu-unk]

• 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

❌ Patch coverage is 0% with 7 lines in your changes missing coverage. Please review.
✅ Project coverage is 77.93%. Comparing base (d5289b9) to head (6408120).

Files with missing lines	Patch %	Lines
src/main/java/com/thealgorithms/maths/Area.java	0.00%	7 Missing ⚠️

Additional details and impacted files

@@ Coverage Diff @@ ## master #6873 +/- ## ============================================ - Coverage 77.95% 77.93% -0.03%  - Complexity 6429 6431 +2  ============================================ Files 736 736 Lines 21476 21483 +7 Branches 4204 4205 +1 ============================================ Hits 16742 16742 - Misses 4060 4068 +8  + Partials 674 673 -1 

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