FIX: Thousands of errors with standard render pipleline and OVR camera

I do not know which version of meta avatar SDK introduced this error.

In 35, the code assumes you are building with URP, if not, you get thousands of errors in the Meta script: AdditionalCameraData.cs

At about line 444, it looks for URP stuff that does not exist and will not exist with standard render pipeline.

Change:

if (!scriptableRenderer.SupportsCameraStackingType(CameraRenderType.Base))

to:

if (scriptableRenderer != null && !scriptableRenderer.SupportsCameraStackingType(CameraRenderType.Base))