Move field validators into annotated types

gso/cli/imports.py

gso/products/product_blocks/site.py

gso/services/partners.py

gso/types/base_site.py

gso/types/country_code.py

gso/types/ip_address.py

gso/types/netbox_router.py

gso/types/site_name.py

gso/types/unique_field.py

gso/workflows/iptrunk/create_iptrunk.py

gso/workflows/lan_switch_interconnect/__init__.py

...lan_switch_interconnect/create_lan_switch_interconnect.py

gso/workflows/site/create_imported_site.py

gso/workflows/site/create_site.py

gso/workflows/site/modify_site.py

gso/workflows/tasks/create_partners.py

gso/workflows/tasks/modify_partners.py