DOCSP-47960: Remove ScalarDiscriminator limitation admonition (#497)

Author: mcmorisi

source/fundamentals/serialization/polymorphic-objects.txt

@@ -161,13 +161,6 @@ you must explicitly list each class you're looking for:
        item.GetType() == typeof(Lion) ||
        item.GetType() == typeof(Tiger));
 
-.. note:: OfType<T>() and the is Operator
-
-   When checking the type of a scalar discriminator, use the ``Where`` syntax shown in
-   the preceding code example. If you try to use the ``Aggregate().OfType<T>()`` method,
-   or if you pass an expression containing the ``is`` operator to the
-   ``Aggregate().Match()`` method, the driver throws an exception.
-
 .. _csharp-discriminator-hierarchical:
 
 HierarchicalDiscriminatorConvention