Don't rely on the built-in interface marshaller during COM activation. (#40228)

Don't rely on the built-in interface marshaller during COM activation. (#40228)

* Don't rely on the built-in marshaller during activation.

Relying on the built-in marshaller leverages the Class interface approach
which doesn't work for some interface types (e.g. interfaces inheriting
from IDispatch).

This approach is wrong regardless of why given that COM dictates the
returned value must be properly cast the specific interface vtable.