fix: NetworkVariable dispose original internal (#3128)

* fix

Assure we dispose the original internal value.

* style

adding some comments and formatting a bit.

Author: NoelStephensUnity

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

@@ -181,19 +181,26 @@ public override void Dispose()
             }
 
             m_IsDisposed = true;
+            // Dispose the internal value
             if (m_InternalValue is IDisposable internalValueDisposable)
             {
                 internalValueDisposable.Dispose();
             }
-
             m_InternalValue = default;
+
+            // Dispose the internal original value
+            if (m_InternalOriginalValue is IDisposable internalOriginalValueDisposable)
+            {
+                internalOriginalValueDisposable.Dispose();
+            }
             m_InternalOriginalValue = default;
+
+            // Dispose the previous value if there is one
             if (m_HasPreviousValue && m_PreviousValue is IDisposable previousValueDisposable)
             {
                 m_HasPreviousValue = false;
                 previousValueDisposable.Dispose();
             }
-
             m_PreviousValue = default;
 
             base.Dispose();