feat: make Google Analytics configurable with VITE_GA_ID

src/setup/constants.ts

···
 export const DISCORD_LINK = "https://discord.gg/gQYB6fGArX";
 export const GITHUB_LINK = "https://github.com/movie-web/movie-web";
 export const DONATION_LINK = "https://ko-fi.com/movieweb";
-export const GA_ID = "G-44YVXRL61C";
+export const GA_ID = import.meta.env.VITE_GA_ID;
 export const BACKEND_URL = import.meta.env.VITE_BACKEND_URL;

src/setup/ga.ts

···
 
 import { GA_ID } from "@/setup/constants";
 
-ReactGA.initialize([
-  {
-    trackingId: GA_ID,
-  },
-]);
+if (GA_ID) {
+  ReactGA.initialize([
+    {
+      trackingId: GA_ID,
+    },
+  ]);
+}