Slice widget causes "Reset Camera" issues after resizing data

[psavery]

When a data source gets resized, "Reset Camera" does not seem to zoom properly if a slice widget is present.

To demonstrate:

1. Start tomviz and open up the recon sample. An outline module and slice module should be present.
2. Bin the volume three times ("Data Transforms"->"Bin Volume x2").
3. Click "Reset Camera".

The view will look like the image below: (Note also that the slice index attempts to remain at whatever number it was before, which results in it being at the edge of the volume, hence the blank blue plane. Also note that the arrow is no longer in the center of the slice, but on the corner.)

4. Now, either delete the slice module, or change the slice module "Direction" to another plane and then switch it back.
5. Click "Reset Camera" again, it should now zoom properly.

I am bringing up this issue in part because it is causing "Reset Camera" issues in #1916.