Add manual sdk init option

Author: webmonch

android/src/main/java/com/intercom/reactnative/IntercomErrorCodes.java

@@ -10,6 +10,7 @@ public class IntercomErrorCodes {
   public static final String SET_LOG_LEVEL = "107";
   public static final String GET_UNREAD_CONVERSATION = "108";
   public static final String SET_USER_JWT = "109";
+  public static final String INITIALIZE_ERROR = "110";
   public static final String DISPLAY_MESSENGER = "201";
   public static final String DISPLAY_MESSENGER_COMPOSER = "202";
   public static final String DISPLAY_CONTENT = "203";