Detect first workflow state as equivalent to creation state

In testing this on our project, I realized that the patch fixed some logic that was duplicated elsewhere in the module. We check whether the workflow state has changed in the case where "Update workflow" is pressed so we can validate it *has* changed, but also when "Save as Draft" is pressed so we can validate is *hasn't* changed. I've refactored the patch to deduplicate the "has it changed" logic and just set the error appropriately in the 2 different places we're checking.

This patch has been operational for a few weeks now. I'm going to commit and cut another beta release to test against.

Automatically closed - issue fixed for 2 weeks with no activity.