SendGrid Integration with Elementor Form widget

## Prerequisites

- [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.**
I've been trying to integrate the newsletter subscription functionality of SendGrid with Elementor's Form widget.
It's been really hard to try to just set up a signup form to create an email list.
I just can't face the fact that Elementor only supports Mailchimp & 3 other providers.
I don't plan on changing my mail service provider just because of this incompatibility.

**Describe the solution you'd like**
Integrate Sendgrid with the Form widget
**Describe alternatives you've considered**
I tried using Zapier but the delay is just too much and that makes it an unusable alternative.
**Additional context**