Bug 32279: Add GetAuthorizedHeading method export C4::AuthoritiesMarc

Bug 32279: Add GetAuthorizedHeading method export C4::AuthoritiesMarc

C4::AuthoritiesMarc method GetAuthorizedHeading is not exported thus it is called in other modules :
 > git grep GetAuthorizedHeading
C4/AuthoritiesMarc.pm:=head2 GetAuthorizedHeading
C4/AuthoritiesMarc.pm:  $heading = &GetAuthorizedHeading({ record => $record, authid => $authid })
C4/AuthoritiesMarc.pm:sub GetAuthorizedHeading {
C4/Breeding.pm:                            $heading = C4::AuthoritiesMarc::GetAuthorizedHeading({ record => $marcrecord });
C4/ImportBatch.pm:            $row->{'authorized_heading'} = C4::AuthoritiesMarc::GetAuthorizedHeading( { authid => $row->{'candidate_match_id'} } );
C4/ImportBatch.pm:    my $authorized_heading = C4::AuthoritiesMarc::GetAuthorizedHeading({ record => $marc_record });

This patch adds it to be exported.
For example for use in Koha plugins.

Test plan :
Check import of authorities from a file is OK

Signed-off-by: Phil Ringnalda <phil@chetcolibrary.org>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>