Fix: getBundleIdentifier Implementation (#1194)

Author: subhankarmaiti

android/src/main/java/com/auth0/react/A0Auth0Module.java

@@ -85,8 +85,9 @@ public A0Auth0Module(ReactApplicationContext reactContext) {
     }
 
     @ReactMethod
-    public String getBundleIdentifier() {
-        return reactContext.getApplicationInfo().packageName;
+    public void getBundleIdentifier(Promise promise) {
+        String packageName = reactContext.getApplicationInfo().packageName;
+        promise.resolve(packageName);
     }
 
     @ReactMethod