Navigation: Fix current-menu-item class logic

[mikachan]

What?

This PR ensures that we are comparing the menu item id as an integer against get_the_ID(), which is also an integer.

Why?

I noticed that the current-menu-item class was no longer being added to the current menu item element in the navigation link block. We need this class to identify the current menu item on the front end (e.g. for styling).

How?

It looks like we were previously comparing get_the_ID() to the menu item's attribute id using a triple ===, which also compares the data type. As the menu item id is a string, comparing these two values would never be true. By adding (int) to the menu item's $attribute['id'], we can successfully compare the type as well as the value.

Testing Instructions

1. Add a navigation block with links to existing internal pages
2. Navigate to a page that's included in the navigation
3. Check that the current-menu-item class is added to the <li> of the current page in the navigation block markup

Screenshots or screencast

Before:

After:

[getdave]

Nice spot. Nice fix 👏