We will soon be converting $wgUser to be a stub
object wrapping a User, and we want to be able
to access the public properties of that object
(doing so will still trigger deprecation warnings,
but it won't break). This will also work for
non-existent properties that are handled via
the __get() and __set() methods of whatever
inner object the StubObject is wrapping.
Bug: T267861
Change-Id: I4c29c615bcb107d4ef8bf4b8e48db2ecf863e5f7
bd73c48744