Fix faulty comparison with typed closure

[muglug]

When an explicit Closure(Foo):Bar type is given this code results in a MixedArgumentTypeCoercion.

It should just be an InvalidArgument: https://psalm.dev/r/0880d5dfe8

Seen in the course of my ongoing deep audit (rewriting most of the logic in Rust, with changes for Hack).

[psalm-github-bot]

I found these snippets:

https://psalm.dev/r/0880d5dfe8

<?php

/** @param Closure(int): string $c */
function takesClosure(Closure $c): void {
	$c(5);
}

takesClosure(5);

Psalm output (using commit 84d6777):

INFO: MixedArgumentTypeCoercion - 8:14 - Argument 1 of takesClosure expects Closure(int):string, parent type 5 provided

[weirdan]

Thanks!