fix: Corehaptics.AssetPickerDrawer throws exceptions and draws incorrectly when fieldInfo or assetType is null

[ilterbilguven]

I'm having problems with collections of ScriptableObjects on inspector.
For example:

using System.Collections.Generic;
using UnityEngine;

public class Test : MonoBehaviour
{
    public List<ScriptableObject> scriptableObjects;
}

It is rendered on inspector like this:

But it was supposed to look like this:

The issue is caused by CoreHaptics.AssetPickerDrawer

This PR fixes this issue by drawing the PropertyField as is, if fieldInfo or assetType is null.

PS: I'm using Unity 6.