title: Android build fails after flavor is added
body: <p>I have a react native application ready for the release, after following the android documentation and have added flavors to the product </p>
  
  <pre><code>flavorDimensions "version"
  productFlavors {
      free {
          dimension "version"
          applicationId 'com.my-app.free'
      }
  }
  </code></pre>
  
  <p><strong>The command <code>react-native run-android</code> fails the gradle build with the following error:</strong></p>
  
  <p>FAILURE: Build failed with an exception.</p>
  
  <ul>
  <li>What went wrong:
  Execution failed for task ':react-native-appboy-sdk:transformClassesWithDexForDebugAndroidTest'.
  
  <blockquote>
    <p>com.android.build.api.transform.TransformException: com.android.ide.common.process.ProcessException: java.util.concurrent.ExecutionException: com.android.dex.DexException: Multiple dex files define Landroid/support/v4/accessibilityservice/AccessibilityServiceInfoCompat;</p>
  </blockquote></li>
  </ul>
  
  <p>Considerations</p>
  
  <ul>
  <li>If I comment the flavor in the gradle file the command runs without any problem.</li>
  <li>Even with this error, I can assemble the apk without any errors using the command <code>./gradlew assembleRelease</code>.</li>
  <li>I can run the app using the android studio run configuration without any errors, this seems to be related to adding flavors and running with the react-native command</li>
  </ul>