An option to force custom icons assets to be loaded on all pages or specific templates

- [x] I have searched for similar features requests in both open and closed tickets and cannot find a duplicate.
- [x] The feature is still missing in the latest stable version of Elementor ( Elementor Pro. )

**What problem is your feature request going to solve? Please describe.**
Currently Elementor is smart enough to load the custom icon resources only when the icons are begin used on the page or template. This is great, but sometimes you want to make use of them programmatically or in a non-Elementor way, and on those cases you'll find the icons are not loaded and unavailable.

**Describe the solution you'd like**
An option on the Custom Icons settings page to always include the assets, or a way to force the assets per-template.

**Describe alternatives you've considered**
Right now I'm solving the problem adding a hidden icon on the header, forcing Elementor to load the assets.

Thanks!