Remove internal setter from collection-type property

[live1206]

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[Copilot]

Pull Request Overview

This PR refactors the collection property initialization mechanism in the Azure Management Generator by removing internal setters and transitioning to constructor-based initialization. The changes simplify the handling of collection-type properties during flattening.

Key changes:

• Replaced method-based initialization with direct constructor initialization for collection properties
• Simplified collection property tracking from dictionary of lists to a simple set
• Removed unnecessary initialization method generation and property setter modifications

Reviewed Changes

Copilot reviewed 2 out of 5 changed files in this pull request and generated 3 comments.

File	Description
FlattenPropertyVisitor.cs	Refactored collection property initialization logic, removed initialization method generation, and simplified property tracking
PropertyHelpers.cs	Updated getter logic to handle collection types without null checks and removed unused collection property population method