refactor(csharp): replace escaped quotes in interpolated strings with raw string literals for clarity

[KaranChadha10]

Description

This PR contains the following points:

• Replaced escaped quotes (") with raw string literals ("""...""") in exception and log messages.
• Removed unnecessary escape sequences, making strings cleaner and easier to read.

Issue link: #520

• I have performed a self-review of my code
• My code follows the style guidelines of this project
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Comments in areas I changed are up to date
• I have added comments to hard-to-understand areas of my code
• I have made corresponding changes to the README.md

[Copilot]

Pull Request Overview

This PR refactors C# code to replace escaped quotes in interpolated strings with raw string literals for improved readability. The changes focus on exception messages in tree data structure implementations.

• Replace escaped quotes (\") with raw string literals ("""...""") in exception messages
• Simplify string formatting by removing unnecessary escape sequences
• Improve code readability across multiple tree data structure classes

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 5 comments.

File	Description
DataStructures/RedBlackTree/RedBlackTree.cs	Updated exception message to use raw string literal
DataStructures/BinarySearchTree/BinarySearchTree.cs	Updated exception message to use raw string literal
DataStructures/AVLTree/AVLTree.cs	Updated two exception messages to use raw string literals
DataStructures/AATree/AATree.cs	Updated exception message to use raw string literal

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[codecov]

Codecov Report

❌ Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 95.19%. Comparing base (88968a4) to head (4b1063f).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
DataStructures/RedBlackTree/RedBlackTree.cs	50.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #527      +/-   ##
==========================================
+ Coverage   95.15%   95.19%   +0.03%     
==========================================
  Files         272      272              
  Lines       10921    10920       -1     
  Branches     1536     1536              
==========================================
+ Hits        10392    10395       +3     
+ Misses        402      400       -2     
+ Partials      127      125       -2     

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[siriak]

Looks good, thanks!