Add missing \n on helloworld gradle.properties (#57113)

Summary:
Add missing \n on helloworld gradle.properties

## Changelog:

[INTERNAL] -

Pull Request resolved: #57113

Test Plan: CI

Reviewed By: fkgozali, Abbondanzo

Differential Revision: D107894162

Pulled By: cortinico

fbshipit-source-id: 71d5ca5a4bde9ae550a6f17bb65a7cfad56d4f4c

Author: cortinico

private/helloworld/android/gradle.properties

@@ -15,4 +15,4 @@ edgeToEdgeEnabled=false
 # Opt out of built-in kotlin and new DSL behavior that ships with AGP 9.
 # Starting from AGP 10.x these opt outs will be removed.
 android.builtInKotlin=false
-android.newDsl=false
+android.newDsl=false