Re-enable newArch on RN-Tester

Summary:
I accidentally turned off New Architecture on RN-Tester while shipping the Fabric Interop. This reverts it.

Changelog:
[Internal] [Changed] - Re-enable newArch on RN-Tester

Reviewed By: cipolleschi

Differential Revision: D45398914

fbshipit-source-id: 2c36f3d0440f147189de644821e1704c00353bac

packages/rn-tester/android/app/gradle.properties

@@ -13,6 +13,6 @@ android.enableJetifier=true
 FLIPPER_VERSION=0.182.0
 
 # RN-Tester is building with NewArch always enabled
-newArchEnabled=false
+newArchEnabled=true
 # RN-Tester is running with Hermes enabled and filtering variants with enableHermesOnlyInVariants
 hermesEnabled=true