Mark rn tester flavours as debuggable

Summary:
Changelog: [Internal]

Debuggable flag defines multiple things for flavours including `NDEBUG` flag in native builds. We need to explicitly state this from build.gradle to use it.

Reviewed By: JoshuaGross

Differential Revision: D26610482

fbshipit-source-id: e0c8095e239241c57a119e561b125cab16bf299f

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

@@ -177,9 +177,11 @@ android {
     }
     buildTypes {
         debug {
+            debuggable true
             signingConfig signingConfigs.release
         }
         release {
+            debuggable false
             minifyEnabled enableProguardInReleaseBuilds
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
             signingConfig signingConfigs.release