[GPT-Codemaster] Fixes issue #3: Refactor ClassExtractorCSharp

[github-actions]

This Pull Request was created automatically by GPT-Codemaster
Resolves #3

[dex3r]

/reviewpad summarize

[reviewpad]

AI-Generated Pull Request Summary: This pull request contains a patch that refactors the ClassExtractorCSharp class in the AiProgrammer.CodeProcessing namespace. The changes improve code readability and maintainability by breaking down the GetClassContentWithSelectedMethodBodies method into smaller, more manageable methods. In particular, the new methods include IsNamespaceDeclaration, HandleNamespaceDeclaration, IsClassDeclaration, HandleClassDeclaration, HandleNextLineNamespace, HandleNextLineClass, and ProcessLine.