DND
1. Enable DND -> Presence is busy DONE
2. Disable DND -> Presence is available DONE
3. Enable DND -> Listeners are notified DONE
4. Disable DND -> Listeners are notified DONE
5. DND remove listener -> listener is no longer notified DONE
6. DND add listener -> Listener is notified DONE
7. Listener is called when first registered DONE
8. Null listeners are ignored DONE
9. Ignores invalid IDs DONE

Extension
1. Enables DND when on DONE
2. Disables DND when off DONE
3. Enables when DND enables DONE INVALIDATED
4. Disables when DND disables DONE INVALIDATED
5. Toggle can enable and disable DND DONE
6. Can destroy toggle when destroyed DONE
7. Toggle reflects initial state of DND DONE INVALIDATED BY TEST 13
8. Displays the indicator when it is on DONE
9. Icon count reflects notification count DONE INVALIDATED
10. Disables DND when disabled DONE
11. Activates by remote DONE
12. Keeps remote in sync DONE
13. Reflects the initial state of the remote DONE
14. Mutes audio when enabled DONE
15. Unmutes audio when disabled DONE
16. Leaves remote on if destroyed DONE
