Update hook for redirect from a FillPdfFieldForm back to its parent FillPdfForm

Issue fork with update hook has been added.

This looks like it would overwrite the config is someone has customized it.

While I have asked Eric put together an update hook that only alters the one attribute, I do sort of wonder what other modules do when they update their views - I feel like there is an argument that any alterations to a view that you don't have full control over should be done programatically, for precisely this type of situation.

And I do feel fairly strongly there should be *some* sort of update hook, because if you're on the older version of the view, you are no longer redirected away from the field editing page when you save, because the update that changed the view also removed the code-based redirect. This makes it seem like the module isn't working.

I have updated the update to now only change the destination option.