Bug 37162: Remove the [% IF ( delete_confirmed ) %] stuff in auth_tag_structure.tt

Bug 37162: Remove the [% IF ( delete_confirmed ) %] stuff in auth_tag_structure.tt

Since auth_tag_structure.pl redirects after deleting when the op is
delete_confirmed (which is actually cud-delete_confirmed) rather than loading
the template, there's no reason to have dead code for IF ( delete_confirmed )
which is both never set, and is never called when anything like it is set.

Test plan:
1. With the patch applied, Administration - Authority types - Chronological
   Term row - Actions menu - MARC Structure
2. You've already verified that auth_tag_structure.tt isn't malformed, but for
   extra fun choose a tag, Actions menu - Delete - Yes, delete and verify that
   it was deleted

Signed-off-by: Sam Lau <samalau@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>