Allow reviewer invitations to be deleted or edited

[lmkw]

Can we use regex to check that email addresses for reviewers are valid?

From a user:
I have a grant on the Competitions system and I accidentally left off the “u” in edu for one of the email addresses for a reviewer. The system did not validate the email address. Took me a while to notice the typo.

[jseraf]

The email address as entered was valid.

User should be able to edit/re-invite or delete an existing invitation.