…less sockets

The issue was that the Socket.SendFile() threw inconsistent exceptions when the platform was Windows and the protocol was UDP.
The first call would throw a SocketException, while the second call would throw a NotSupportedException.

With this commit, SendFile() will consistently throw NotSupportException on all platforms when the protocol is UDP.

Fix #47472

…r `!Connected`.

Before:.

    Throws `NotSupportedException` on UDP.

After:

    Throws `NotSupportedException` if `!IsConnectionOriented` or `!Connected`.

…f platform.

….Tasks.cs

Co-authored-by: Karel Zikmund <karelz@microsoft.com>