Bug 22389: (bug 15836 follow-up) Add Delete regex links on creating splitting source

Bug 22389: (bug 15836 follow-up) Add Delete regex links on creating splitting source

The "Delete" link does not exist when the form is empty.

Test plan:
Create a new classification splitting source
Select "Regex" for routine
=> The delete link does not appear (you cannot remove if there is only
one input)
=> It a regex
=> The 2 delete links appear

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
(cherry picked from commit 63c5a813c994a4893eaef2cb87fcd26bc594c3e4)
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>