[FEATURE] Add result_format as argument to batch.validate

[tyler-hoffman]

See title.

Other stuff

• Creates a single union type for all the things result format can be
• Adds a constant for the default result format

• [ ] Description of PR changes above includes a link to an existing GitHub issue
• [ ] PR title is prefixed with one of: [BUGFIX], [FEATURE], [DOCS], [MAINTENANCE], [CONTRIB]
• [ ] Code is linted - run invoke lint (uses ruff format + ruff check)
• [ ] Appropriate tests and docs have been updated

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