Bug 21958: Allow 'e' subfield for authorities

Bug 21958: Allow 'e' subfield for authorities

This bug specifically changed the code to allow for e in authority record

This is a tricky issue, see link for discussion:
https://www.loc.gov/marc/marbi/2008/2008-dp05-1.html

It seems to be allowed, but possibly not useful?

In either case I think for now we can allow in the test to fix this error
and possibly open a new bug for further discussion

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>