Bug 17798: Add fieldset for 'Yes, check out (Y)'

Bug 17798: Add fieldset for 'Yes, check out (Y)'

With the increased text, the buttons don't arrange neatly. Adding a
fieldset around the options for 'Yes' mitigates this somewhat - it
could do with a bit more styling, however, it also fixes bug 23953

To test:
Confirm the 'Yes' options are more clear that they only affect the yes
button
Confirm the other buttons arrange nicely

Signed-off-by: Owen Leonard <oleonard@myacpl.org>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
(cherry picked from commit 5d291a6f1d9df762232379bc214753953c2d672e)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>