Reset of bone proxy in anim editors detail panels doesn't re-enable live update of tranforms

The bone proxy details customization for the animation editors doesn't currently reset modifications correctly.  When a transform channel is modified and then reset, the bone proxy doesn't start live updating with the animation correctly again as it would have been doing prior to any modification.

1. Open an anim sequence in the anim editor
2. Select a bone
3. Note how, in the details panel, the transform values update with the animation
4. Change the value of one of the transform channels
5. Note how the values no longer live update
6. Hit the reset button
   1. Expected behaviour: transforms should return to animation and re-start live updating
   2. Actual behaviour: transforms return to ref-pose for that bone and do not live update with the animation