chore: remove extra newline in println (#9850)

## Summary

This PR makes a minor formatting adjustment to a `println!` message by
removing an extra empty line and explicitly using `\n` for clarity.

## Changes

- Adjusted console output formatting for the success message.
- No functional or behavioral changes.

codex-rs/cli/src/main.rs

@@ -396,8 +396,7 @@ fn run_update_action(action: UpdateAction) -> anyhow::Result<()> {
     if !status.success() {
         anyhow::bail!("`{cmd_str}` failed with status {status}");
     }
-    println!();
-    println!("🎉 Update ran successfully! Please restart Codex.");
+    println!("\n🎉 Update ran successfully! Please restart Codex.");
     Ok(())
 }