Fix tests explicitly written to take a long time

[stephentoub]

Some of the tests take obscene amounts of time, e.g.

csharp-sdk/tests/ModelContextProtocol.Tests/ClientIntegrationTests.cs

Lines 291 to 301 in 5171ccc

	await Task.Delay(10000, TestContext.Current.CancellationToken);
	// reset counter
	int counterAfterSubscribe = counter;
	// unsubscribe
	await client.UnsubscribeFromResourceAsync("test://static/resource/1", CancellationToken.None);
	counter = 0;
	// notifications happen every 5 seconds, so we wait for 10 seconds to ensure we would've gotten at least one notification
	await Task.Delay(10000, TestContext.Current.CancellationToken);

These should be written to not require such long pauses.

[halter73]

Fixed by #122/#142