Turn off Metro JS Deltas by default for Android

Summary: JS Deltas have been killing productivity of RN engineers lately. There's been several posts and questions asked that end in "Turn off JS Deltas". Disabling them until we can make them more stable.

Reviewed By: fkgozali

Differential Revision: D14491774

fbshipit-source-id: 29b1c8e5e72369882c2890e3b6347ecd2fe4bed1

ReactAndroid/src/main/res/devsupport/xml/rn_dev_preferences.xml

@@ -23,7 +23,7 @@
  android:key="js_bundle_deltas"
  android:title="Use JS Deltas"
  android:summary="Request delta bundles from metro to get faster reloads (Experimental)"
- android:defaultValue="true"
+ android:defaultValue="false"
  />
  <CheckBoxPreference
  android:key="js_bundle_deltas_cpp"