Disable Metal on Mac for now (import problems with some of the compute shaders, being looked at)

ProjectSettings/ProjectSettings.asset

   - m_BuildTarget: WindowsStandaloneSupport
     m_APIs: 0200000001000000
     m_Automatic: 1
+  - m_BuildTarget: MacStandaloneSupport
+    m_APIs: 11000000
+    m_Automatic: 0
   m_BuildTargetVRSettings:
   - m_BuildTarget: Android
     m_Enabled: 0