Add comments explaining nested task

Author: daymxn

FirebaseAI/Sources/Types/Internal/Live/LiveSessionService.swift

@@ -115,8 +115,11 @@ actor LiveSessionService {
   /// resuming the same session.
   func connect() {
     setupTask.cancel()
+    // we launch the setup task in a seperate task to avoid blocking the parent context
     setupTask = Task { [weak self] in
+      // we need a continuation to surface that the setup is complete, while still allowing us to listen to the server
       try await withCheckedThrowingContinuation { setupContinuation in
+        // nested task so we can use await
         Task { [weak self] in
           guard let self else { return }
           await self.listenToServer(setupContinuation)