assert_connected does not work with anonymous functions

# Versions
*(list all versions where you have replicated the bug)*
* Godot: 4.5.1
* GUT: 9.5.1
* OS: MacOS


# The Bug
The following test fails:
```gdscript
func test_demo_issue():
	var btn = autofree(Button.new())
	var f = func(): print('hello')
	btn.pressed.connect(f)
	assert_connected(btn.pressed, f)
```


