test: add test updating signal from multi-calls in effect

[aralroca]

Fixes https://github.com/brisa-build/brisa/issues/478

The issue cannot be reproduced anymore, I've added the test so that it will not happen again. It was probably solved in this other PR: https://github.com/brisa-build/brisa/pull/480

[pkg-pr-new[bot]]

Open in Stackblitz

brisa-adapter-vercel

``` bun add https://pkg.pr.new/brisa-build/brisa/brisa-adapter-vercel@590 ```

brisa

``` bun add https://pkg.pr.new/brisa-build/brisa@590 ```

brisa-pandacss

``` bun add https://pkg.pr.new/brisa-build/brisa/brisa-pandacss@590 ```

brisa-tailwindcss

``` bun add https://pkg.pr.new/brisa-build/brisa/brisa-tailwindcss@590 ```

create-brisa

``` bun add https://pkg.pr.new/brisa-build/brisa/create-brisa@590 ```

www

``` bun add https://pkg.pr.new/brisa-build/brisa/www@590 ```

commit: 6002c63