sGTM - add X-Gtm-Server-Preview Header

GA4 & Server-Side Tag Manager debugging helper. This tool helps debug your tracking setup with two key features: 1. It adds the X-Gtm-Server-Preview header to all requests. While there are other "add header value" plugins available, they can cause issues if left enabled, leading to unpredictable behavior when working on another sGTM. This extension includes an auto-deactivation feature: it automatically disables itself after one hour, ensuring a seamless and hassle-free debugging experience. 2. It adds a _dbg=1 parameter to all GA4 requests to enable debug mode for all GA4 requests, making it very simple to debug GA4. TL;DR: Add a sGTM preview header value to all requests or enable debug mode for GA4.