WIP - Fix subscribing when Background Modes are off and Direct To History is enabled

[jkasten2]

Issue

If Background Modes are off under Xcode > Capabilities AND iOS "Enable iOS 12 Direct To History" is enabled on the OneSignal dashboard settings the player will be created with the following on the dashboard;"Provisioning Profile Missing Push Permission"

The SDK reports notification_types as 80 and no identifier.

Also calling OneSignal.promptForPushNotificationsWithUserResponse says that it is disabled when it isn't and won't show a prompt.

TODO

1. registerForAPNsToken needs to check for notifPermissionState.provisional.

• Complete in commit 37a4d6f

1. We need to delay calling registerForAPNsToken until the download params completes.
2. Write unit test reproducing issue

This change is 

[jkasten2]

This PR is approved however incomplete so do not merge it yet!

[emawby]

Prompting for full push now works as intended but the dashboard still shows "Provisioning Profile Missing Push Permission". What should we be displaying if background push is off?