Javadoc
Checks that each of the receivers associated with the three actions defined in
ParsePushBroadcastReceiver (ACTION_PUSH_RECEIVE, ACTION_PUSH_OPEN, ACTION_PUSH_DELETE) has
their exported attributes set to false. If this is the case for each of the receivers
registered in the AndroidManifest.xml or if no receivers are registered (because we will be registering
the default implementation of ParsePushBroadcastReceiver in PushService) then true is returned.
Note: the reason for iterating through lists, is because you can define different receivers
in the manifest that respond to the same intents and both all of the receivers will be triggered.
So we want to make sure all them have the exported attribute set to false.