Fix broken sorting metadata caused by incorrect accessors, field
references, and naming mismatches in several table definitions.
Update accessor paths for provider_account and device order_by; add
order_by mapping for the is_active property column; correct field name
typos such as termination_count to terminations_count; rename the
ssl_validation column to ssl_verification to match the model field; and
mark computed columns as orderable=False where sorting is not supported.
Fixes#21825
Adds ContactsMixin to VirtualCircuit model and GraphQL type, and includes
'contacts' in table fields. Verified: UI Contacts tab, REST API POST (201),
GraphQL contacts query.
