Fix DecalProjector material editor release (64 preview issue)

Fix FB#1057395 for DecalProjector.

com.unity.render-pipelines.high-definition/HDRP/Editor/Material/Decal/DecalProjectorComponentEditor.cs

             m_DecalProjectorComponent.OnMaterialChange -= OnMaterialChange;
         }
 
+        private void OnDestroy()
+        {
+            DestroyImmediate(m_MaterialEditor);
+        }
+
         public void OnMaterialChange()
         {
             // Update material editor with the new material