revert unwanted commits

com.unity.perception/Runtime/GroundTruth/Labelers/Visualization/Materials/SegmentationMaterial.mat

         m_Offset: {x: 0, y: 0}
     m_Floats:
     - _AlphaClip: 1
-    - _BackTransparency: 1
+    - _BackTransparency: 0
     - _Blend: 2
     - _BlendOp: 0
     - _BumpScale: 1
     - _QueueOffset: 0
     - _ReceiveShadows: 1
     - _SampleGI: 0
-    - _SegmentTransparency: 1
+    - _SegmentTransparency: 0.8
     - _Shininess: 0
     - _Smoothness: 0.5
     - _SmoothnessSource: 0

com.unity.perception/Runtime/GroundTruth/Labeling/LabelEntryMatchCache.cs

             World.DefaultGameObjectInjectionWorld?.GetExistingSystem<GroundTruthLabelSetupSystem>()?.Deactivate(this);
             m_InstanceIdToLabelEntryIndexLookup.Dispose();
         }
-
-        public void ClearCache()
-        {
-            m_InstanceIdToLabelEntryIndexLookup.Clear();
-        }
-
     }
 }