Make jid_is_valid() allow JIDs ending with a slash (`user@domain/`). In these cases, the parser now treats the input as a Bare JID with no resource part, rather than rejecting it as invalid. We will then just get `user@domain`.
Make jid_is_valid() allow JIDs ending with a slash (`user@domain/`). In these cases, the parser now treats the input as a Bare JID with no resource part, rather than rejecting it as invalid. We will then just get `user@domain`.