Remove NDK reference from sample app (#4597)

Summary:
Pull Request resolved: https://github.com/facebook/flipper/pull/4597

Not needed. The sample app doesn't have any C++ code.

Reviewed By: aigoncharov

Differential Revision: D44028696

fbshipit-source-id: 0e21e0eda1ff99dae8900fbcd4452b73745d7aa3

react-native/ReactNativeFlipperExample/android/app/build.gradle

@@ -133,8 +133,6 @@ def enableHermes = project.ext.react.get("enableHermes", false);
 def nativeArchitectures = project.getProperties().get("reactNativeDebugArchitectures")
 
 android {
-    ndkVersion rootProject.ext.ndkVersion
-
     compileSdkVersion rootProject.ext.compileSdkVersion
 
     defaultConfig {

react-native/ReactNativeFlipperExample/android/build.gradle

@@ -12,7 +12,6 @@ buildscript {
         minSdkVersion = 21
         compileSdkVersion = 31
         targetSdkVersion = 31
-        ndkVersion = "$NDK_VERSION"
     }
     repositories {
         google()