Add widget ID to group annotation callback.

Summary:
The number is very useful in order to know in what order rendering
occurred, but getting any additional information on the widget is
difficult with just the number.

In the case that prompted this change, I needed to figure out the score
for the group widget, which is provided via a mapping from widget IDs
to score objects.

Test Plan:
Verified that arguments provided to the group annotation function were
reasonable and coincided with the correct widget.

[NOT LANDED D14606]
Adds callback to restore serialized state.

Summary:
restoreSerializedState changes the state of various react components
and so is not synchronous. Previously there was no way to tell when the
operation was complete. Now a callback is fired once the state has been
fully restored.

Test Plan:
Ran through various items with groups, passages, and simple radio
buttons and ensured that the state had been fully restored before the
callback was fired.

[NOT LANDED D14604]
Doh, debug message.

[NOT LANDED D14604]