Limit the maximum value of unbinds in the connection dialog to signal_argument_size

[Rindbee]

Previously, the range of unbinds was the default range of SpinBox ([0, 100]), now the maximum value is limited to the size of the parameter list of the Signal.

And the value of unbinds is taken into account when generating the parameter list of the Receiver Method.

I found Script::has_script_signal and Script::get_script_signal_list, but there is no Script::get_script_signal.

[KoBeWi]

The unbinds spinbox could get disabled if max is 0, so users wouldn't wonder why it's non-functional.

[Rindbee]

For parameters in the final Receiver Method parameter list, if divided by where they come from, currently, they can be divided into 3 categories, as I explained with different colors in the picture of #60143 (comment) (there, I added another one, the signal source, to increase flexibility of the connection dialog).

[KoBeWi]

Looks ok.

As for the disabling the SpinBox I mentioned earlier, when the method has 0 arguments, the max value of unbind is 0. The SpinBox can still be interacted with, but clicking or typing anything has no effect. It might be confusing to some people, so maybe it would be better to disable it explicitly. But maybe I'm wrong. It's not that important.

[akien-mga]

Thanks!