Guestbook email field does not check email validity

[DS-INRAE]

What steps does it take to reproduce the issue?

• Set a guestbook on a dataset
• Attempt downloading files from the dataset
• Enter a value in the email field of the guestbook which isn't a correct email
• Voilà !

When does this issue occur?
With any guestbook

Which page(s) does it occurs on?
Guestbook (therefore dataset page and preview tab of files page)

What happens?
Email are not checked

To whom does it occur (all users, curators, superusers)?
File downloaders/explorers

What did you expect to happen?
Verify that the email address inputed is actually an email address

Which version of Dataverse are you using?
v5.14 (also seen on Demo Dataverse running v6.2)

Any related open or closed issues to this bug report?
Functionally unrelated but on guestbook checks :

• Creating a guestbook with a custom question that has more than 255 characters says "success" but silently fails #9492

Screenshots:

Screencast.from.2024-07-01.14-17-20.mp4

[qqmyers]

related to #10625

[DS-INRAE]

Related to the discussion on zulip on validators for guestbook, as that would impact the API part for these fields : https://dataverse.zulipchat.com/#narrow/stream/379673-dev/topic/metadata.20validators.20per.20field/near/449952746

[cmbz]

2024/08/19

• This could also impact frontend (we would want validation in UI as well as backend)