[CSP] Add support for nested properties to CSP build

[SimoTod]

This PR adds a minimal enhancement to the CSP build to support nested properties via dot notation (property accessor).

<div x-data="counter">
    <button @click="foo.increment">Increment</button>
    <span x-text="foo.count"></span>
</div>

Alpine.data('counter', () => ({
    foo: {
        count: 1,

        increment() {
            this.count++
        },
    },
}))

The build size is pretty much the same and it seems a reasonable change otherwise dev using the csp build are forced to flatten the component and put all properties at the top.

I only know about one user mentioning it though so feel free to close it if you think it's not worth it for now.

[calebporzio]

This is great. Thanks Simone!