perf(networked-vars): Skip NetworkList set operation when value unchanged

Added equality check in NetworkList indexer setter to avoid unnecessary operations when the new value equals the existing value. This improves performance by preventing redundant list events and network synchronization.

Author: harayuu9

com.unity.netcode.gameobjects/Runtime/NetworkVariable/Collections/NetworkList.cs

@@ -617,6 +617,13 @@ public T this[int index]
                 }
 
                 var previousValue = m_List[index];
+
+                // Compare the Value being applied to the current value
+                if (NetworkVariableSerialization<T>.AreEqual(ref previousValue, ref value))
+                {
+                    return;
+                }
+
                 m_List[index] = value;
 
                 var listEvent = new NetworkListEvent<T>()