🧪 Add missing tests for ObjectExtensions

[johnstrand]

🎯 What: The testing gap addressed for ObjectExtensions.
📊 Coverage: Added test coverage for Mutate, Out, and Curry methods.
✨ Result: Improved test coverage for ObjectExtensions.cs to catch regressions.

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PR created automatically by Jules for task 59243819345564543 started by @johnstrand

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