fix(weave): support eval_results filtering on inputs

[domphan-wandb]

Description

• https://coreweave.atlassian.net/browse/WB-32712

This PR fixes a few issues with filtering and sorting capabilities on imperatively logged evals because they don't have an actual dataset.

Problem

Filtering and sorting on inputs.* was returning empty results whose row_digest had no matching row in table_rows.

• The query builder buildsresolved_inputs with COALESCE(tr.val_dump, JSONExtractRaw( inputs_dump, 'example'))
  • tr is the result of a LEFT JOIN on the row digest.
  • If the row digest is null, like in the case of imperatively logged evals, then Clickhouse fills the result with the default value, '', because val_dump is a non nullable string.

COALESCE will always return the empty string, which makes sorting and filtering broken on inputs.

To fix this, the PR adds nullIf calls on the val_dump so that the COALESCE can actually fallthrough to the example.

Testing

How was this PR tested?

• Against dev frontend
• unit tests updated

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!