Automatically Call DisposeAsync

[sophiatev]

It's unsafe to rely on a user calling DisposeAsync once they're done using the enumerator exposed by SqlAsyncEnumerable. If they do not call it, the SqlConnection and SqlDataReader will remain open, leaking resources. Ideally, we should find a way to have this method be called automatically once the user's function exits.

[Charles-Gagnon]

Check if other extensions do anything for this.