BLOG-112 refactor: simplify Google Analytics script initialization and remove gtag declaration from Window interface

frontend/src/app.d.ts

@@ -18,7 +18,6 @@ declare global {
 
 	interface Window {
 		dataLayer: unknown[];
-		gtag: (command: 'config' | 'set' | 'js' | 'event', ...args: unknown[]) => void;
 	}
 }
 

frontend/src/lib/common/framework/ui/GoogleAnalytics.svelte

@@ -1,4 +1,4 @@
-<script lang="ts">
+<script lang>
 	import { Environment } from '$lib/environment';
 	import { onMount } from 'svelte';
 
@@ -19,10 +19,10 @@
 		document.head.appendChild(gaScript);
 
 		window.dataLayer = window.dataLayer || [];
-		window.gtag = (command: 'config' | 'set' | 'js' | 'event', ...args: unknown[]) => {
-			window.dataLayer.push(command, ...args);
-		};
-		window.gtag('js', new Date());
-		window.gtag('config', gaMeasurementId);
+		function gtag() {
+			window.dataLayer.push(arguments);
+		}
+		gtag('js', new Date());
+		gtag('config', gaMeasurementId);
 	});
 </script>