Bug 15731: Remove C4::Reports::Guided::build_authorised_value_list

Bug 15731: Remove C4::Reports::Guided::build_authorised_value_list

This subroutine has been added by
  commit 42acfbf75b7bb4ee53c6a6f035e258a0b522ce10
  Bug 7993: Save reports with Group/Subgroup hierarchy

But it has never been used (or git grep cheats me).

Test plan:
1/ git grep build_authorised_value_list
should not return any result
2/ Create a report, execute it
Everything should work fine.

Signed-off-by: Hector Castro <hector.hecaxmmx@gmail.com>
Works as advertised

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Brendan Gallagher brendan@bywatersolutions.com