Ensure MaterialInstance copies all properties from source (#222)

Added a call to `output.CopyPropertiesFromMaterial(source)` in the `Instance` method of `MaterialInstance.cs`. This ensures that the newly created `output` material inherits all properties from the `source` material, maintaining consistency between them.

Author: breezinstein

com.microsoft.mrtk.graphicstools.unity/Runtime/Utilities/MaterialInstance.cs

@@ -51,6 +51,7 @@ public static Material Instance(Material source)
             }
 
             Material output = new Material(source);
+            output.CopyPropertiesFromMaterial(source);
             output.name += InstancePostfix;
 
             return output;