⚡ Optimize GetComponent to TryGetComponent in GPUInstancerPrefabManager

[marko1olo]

💡 What:
Replaced multiple GetComponent calls inside the SetRenderersEnabled method with TryGetComponent to fetch LODGroup and Rigidbody components.

🎯 Why:
The GetComponent method creates unnecessary garbage collection allocations and C++/C# boundary overhead when a component does not exist. Since TryGetComponent evaluates in C++ and safely returns false without allocating a C# stub, replacing these inside frequently called rendering blocks significantly optimizes instance processing paths.

📊 Measured Improvement:
Because the solution structure lacks local console runner testing compatibility and Unity tests are filtered out of the explicit CLI runner, standard .NET benchmarks could not directly measure the Unity boundary improvement programmatically in this environment. However, documentation indicates this reliably improves single-component checking overhead by avoiding allocating null wrapper objects, improving runtime CPU and GC times.

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PR created automatically by Jules for task 3244040335269934407 started by @marko1olo

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