Bug 26971: Remove obsolete test file translatable-templates.t

Bug 26971: Remove obsolete test file translatable-templates.t

After bug 25067 we found that this test file is failing with

 #   Failed test 'opac_bootstrap templates are translatable'
 #   at xt/author/translatable-templates.t line 91.
 # Unknown action specified.

The original patches forgot to update this file.
However when we tried to adjust it, we found that those tests are never working.

Tried on 18.11.00 with a very ugly modified intranet-main.tt, the test was still passing.

No idea how we can make it display warnings and so hard to fix the expected behaviour.

I decided to remove it for now and see later if we need an updated test for the translate script.

See also 25067 comment 84

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