Track UI launches

Summary: This is currently done by querying the 'console-log' event. Instead, make it type safe and official.

Reviewed By: antonk52

Differential Revision: D50927713

fbshipit-source-id: 780c0f158bf8bdaa6d009035a0cee62c7828f479

desktop/flipper-server/src/index.tsx

@@ -313,6 +313,11 @@ async function launch() {
     console.info(`[flipper-server] Go to: ${chalk.blue(url.toString())}`);
 
     open(url.toString(), {app: {name: open.apps.chrome}});
+
+    tracker.track('server-open-ui', {
+      browser: true,
+      hasToken: token?.length != 0,
+    });
   };
 
   if (argv.bundler) {
@@ -320,6 +325,10 @@ async function launch() {
   } else {
     const path = await findInstallation();
     if (path) {
+      tracker.track('server-open-ui', {
+        browser: false,
+        hasToken: token?.length != 0,
+      });
       open(path);
     } else {
       await openInBrowser();