Godot 4 Yield To Fix

[Tim-Fronsee]

Summary

Fixes yielding (awaiting) for signals in Gut in Godot 4.

For testing, I used a simple GutTest which emits a button press (below);

func test_pressed():
	var button = autofree(SomeButton.new())
	add_child(button)
	await yield_to(button, "pressed", 1).timeout
        button.emit_signal("pressed")
	assert_signal_emitted(button, "pressed")