Copy labels dynamically in ApprovalsUtil.byPatchSet

The intent is to use this method from ChangeJson to dynamically copy
labels every time the change detail is loaded, thus not relying on
one-time copying of labels in the notedb read path.

To do so requires a bit of refactoring, since the ChangeControl now
needs to be passed into this method.

Change-Id: I8bc25d32a91218e074517dcacf4bf3a77d4ae957
14 files changed