Script Loader: Preserve duplicate URL query params in enqueued scripts and styles.

Previously in r61397, `add_query_arg()` was used to append versions or handle-specific query arguments. This resulted in stripping any existing duplicate query variables in the source URL (common in Google Fonts URLs). This change refactors `WP_Styles::_css_href()` and `WP_Scripts::do_item()` to manually append these parameters to the URL string. This ensures all original query variables are preserved exactly as provided. It also improves fragment handling by ensuring query parameters are inserted before any '#' anchor while maintaining the anchor's presence.

The URL encoding changes in `tests/phpunit/tests/dependencies/scripts.php` are reversions of what had previously been done in r61397.

Developed in https://github.com/WordPress/wordpress-develop/pull/11164

Follow-up to r61397, r61358.

Props westonruter, jonsurrell.
Fixes #64372.


git-svn-id: https://develop.svn.wordpress.org/trunk@61927 602fd350-edb4-49c9-b593-d223f7449a82