Support code_version for dbt seeds by default

[goober]

What's the use case?

Seed assets in dbt does not provide a valid code_version.

Rationale

To be able to use the AutomationCondition.code_version_changed() condition to trigger a materialization when a seed file is updated.

Ideas of implementation

The current implementation of default_code_version_fn in DagsterDbtTranslator will only take the raw_sql or raw_code from the manifest.json into consideration when calculating the code version for a dbt asset. However, this value is empty for seed assets. With the latest release including #25387 makes it possible to handle this by overriding the get_code_version and return dbt_resource_props["checksum"]["checksum"] which is the file checksum for the seed csv.

Instead of forcing everyone that wants to handle a correct code_version for seed assets to override this function it is suggested that the default_code_verson_fn is updated to return the file checksum if it is available.

Additional information

If the improvement is accepted I would be happy to provide a PR.

Message from the maintainers

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