Remove asterisk after adding required field (reference)

[vanaukenk]

Once a curator has added a reference to that required field, for clarity, the asterisk should go away so the curator knows the information has been entered correctly.

[vanaukenk]

If evidence is added and the reference goes to grey, that's okay, but if you accidentally start entering information and remove it, then the evidence and/or reference goes to red even if the field is blank. Curators can still save, but it's confusing to have the red text.