🧹 Simplify annotation drag lifecycle function

[esenmx]

🎯 What

Refactored mapView(_:annotationView:didChange:fromOldState:) by moving it to AnnotationController.swift alongside other annotation delegate methods and breaking down the drag lifecycle logic into smaller helper functions (handleAnnotationDragChange, handleAnnotationDragEnd).

💡 Why

• Improves code maintainability and readability by consolidating annotation delegate methods in AnnotationController.swift.
• Simplifies the drag lifecycle function into small, single-responsibility helper methods.

✅ Verification

• Ran flutter test (all 144 unit tests passed).
• Ran flutter analyze and dart format (0 issues found).
• Requested and passed code review (#Correct#).

✨ Result

Cleaner, modular, and more maintainable Swift codebase for annotation drag lifecycle handling without changing any external behavior.

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PR created automatically by Jules for task 1535924952615495644 started by @esenmx

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