Don't use setLayoutAnimationEnabledExperimental in RNTester AnimatedGratuitousApp

Summary:
Context: in non-Fabric (classic) RN, LayoutAnimations is disabled by default on Android; and this is needed to enable LayoutAnimations globally for Android.

Reasoning: in Fabric this noops, because LayoutAnimations are unconditionally enabled in Android+Fabric; and to support StaticViewConfig and Bridgeless RN, we need to remove direct UIManager calls.

Potential impact: On Android and for non-Fabric users only, some transitions will not be animated. Given that LayoutAnimations in non-Fabric RN on Android are not stable and have lots of known un-fixable crashes, this will probably increase stability for non-Fabric Android users. For iOS or Fabric users there's no impact.

Changelog: [Changed][Android] LayoutAnimations in AnimatedGratuitousApp disabled for non-Fabric Android devices

Reviewed By: mdvacca

Differential Revision: D27273392

fbshipit-source-id: 786d5d2f2b05591ca747aab134fb3f321500fece