Bug 35125: Respect LinkerConsiderThesaurus in get_link

Bug 35125: Respect LinkerConsiderThesaurus in get_link

This patch adds a new key 'notconsidered' to the authority cache when
linking to avoid doubling when creating new authorities and wishing
to ignore thesaurus

To test:
0 - Set LinkerConsiderThesaurus to "don't"
1 - Set AutCreateAuthorities to generate
2 - Set AutLinkBiblios to Do
3 - Set CataloguingModuleRelink to Do
4 - Save a new record in Koha with the same randomized heading repeated
    but from 3 different authority sources
    ensure source is defined by indicators only and by field $2 once
    ensure the heading is random so that no matches will be found
5 - Confirm each authority is linked to a new unique authority
6 - Apply patch, restart all
7 - Repeat 4 with a new subject heading
8 - Confirm all headings are linked to the same authority

Signed-off-by: Phil Ringnalda <phil@chetcolibrary.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>