[CT-3334] Remove usage of dbt.contracts.graph.nodes.ConstraintType, ColumnLevelConstraint, ModelLevelConstraint in dbt/adapters

[MichelleArk]

Housekeeping

• I am a maintainer of dbt-core

Short description

dbt.contracts.graph.nodes.ConstraintType is used in dbt/adapters in:

• BaseAdapter.CONSTRAINT_SUPPORT
• BaseAdapter.process_parsed_constraint
• PostgresAdapter.CONSTRSAINT_SUPPORT
  for the purposes of rendering python constraints objects to DDL during materializations. ConstraintType is also used in parsing and

ColumnLevelConstraint and ModelLevelConstraint are used for similar purpose in dbt/adapters

Additionally, these classes are used in parsing and are part of the serialized manifest in core

Implementation options:

• define these dbt.contracts.graph.nodes outside of core - either in dbt.common.contracts or dbt.adapters.contracts + update import paths
• keep the existing node classes in core, but define separate protocols or dataclasses in adapters for passing data between core and adapters - this will involve some duplication but may be beneficial if the adapters module does not need everything functional in these classes provided by core, but just the data / schemas.

Acceptance criteria

The following adapter interfaces no longer rely on dbt.contracts.graph.nodes.ConstraintType:

• BaseAdapter.CONSTRAINT_SUPPORT
• BaseAdapter.process_parsed_constraint
• PostgresAdapter.CONSTRSAINT_SUPPORT

Impact to Other Teams

1p adapter imports will need to be updated, but those can be done separately as part of a bundled migration of 1p for #8917 if the work is done on a feature branch: #8906

Will backports be required?

No

Context

No response