add ability to get user from initialize

Author: silesky

.changeset/sixty-chicken-wave.md

@@ -0,0 +1,10 @@
+---
+'@segment/analytics-next': minor
+---
+
+Initialize should actually support getting the initialized analytics instance.
+
+```ts
+analytics.on('initialize',function ({ analytics }) {
+  console.log('initialize', analytics.user()) // this works now.
+})

packages/browser/src/browser/index.ts

@@ -308,7 +308,16 @@ async function loadAnalytics(
   )
 
   analytics.initialized = true
-  analytics.emit('initialize', settings, options)
+  analytics.emit(
+    'initialize',
+    {
+      writeKey: settings.writeKey,
+      cdnSettings: settings.cdnSettings,
+      analytics: analytics,
+    },
+    /* @deprecated -- can just use analytics.options */
+    options
+  )
   await flushFinalBuffer(analytics, queryString, preInitBuffer)
 
   return [analytics, ctx]