Bug 24151: Use fully qualified names for UpdateStats

Bug 24151: Use fully qualified names for UpdateStats

t/db_dependent/Koha/Account/Line.t .. 8/12     # Looks like you planned 16 tests but ran 3.
 #   Failed test 'void() tests'
 #   at t/db_dependent/Koha/Account/Line.t line 723.
Undefined subroutine &Koha::Account::UpdateStats called at /kohadevbox/koha/Koha/Account.pm line 289.

It's certainly caused by a circ dep from
  commit 5ce968e0e571f555261c02a9e1d27447611cdb89
  Bug 24151: Copy info to the pseudonymized table when a transaction is done

See also bug 17600 for more context.

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