iAPI Router: Only load modules of interactive blocks on client-side navigation

[DAreRodz]

What problem does this address?

The current iAPI Router implementation simply looks for all JavaScript modules in the HTML and imports them. However, some of them may not be necessary, potentially executing code that is neither related to interactive blocks nor compatible with the Interactivity API.

What is your proposed solution?

We could implement a mechanism that tells the iAPI router which JavaScript modules to consider and which to ignore. Some sort of "allowlist" would be fine.

[luisherranz]

We could use data-wp-router-options={ "loadOnClientNavigation": true } to standardize all the different options for the router, and we should add it only to the viewScriptModules of blocks with supports.interactivity: true.

[luisherranz]

We could do as follows:

1. Introduce a new load_on_client_navigation arg on the wp_register_script_module function. When it's true, it adds an data-wp-router-options={ "loadOnClientNavigation": true } attribute to the script.
2. Each time we detect an interactive block (here), pass load_on_client_navigation => true.
3. In the router navigation, filter the script modules and only load the ones with that attribute option.

[DAreRodz]

Reopening this as the backport PR is not ready yet,