[VSCRIPT] Static member serialisation crash

### Describe the bug
Object type is not recognised in `SquirrelVM::ReadObject`, triggering the `Error` in the default switch case.

Tested in the current `develop` branch before 7.0.

### Steps to reproduce
Save and load a class instance with static members:

```cs
class CTest
{
	static var = null
}

instance <- CTest()
```