Don't export null HYDRO_DATA_ACTIONS records

[randywoods]

🗣 Description

Don't blindly write a null HYDRO_DATA_ACTIONS record for every ANSWER record. Also on import, don't attempt to import a row that has no values.

This is the cause of all the DBIO exceptions showing up in the NLog table. A null record was being created for every ANSWER record being exported if the assessment is not a Hydro assessment. If the user tries to import that export, it would build an INSERT statement with nothing between the parentheses in the VALUES clause of the statement.

💭 Motivation and context

🧪 Testing

✅ Pre-approval checklist

• This PR has an informative and human-readable title.
• Changes are limited to a single goal - eschew scope creep!
• All future TODOs are captured in issues, which are referenced
  in code comments.
• All relevant type-of-change labels have been added.
• I have read the CONTRIBUTING document.
• These code changes follow cisagov code standards.
• All relevant repo and/or project documentation has been updated
  to reflect the changes in this PR.
• Tests have been added and/or modified to cover the changes in this PR.
• All new and existing tests pass.

✅ Pre-merge checklist

• Revert dependencies to default branches.
• Finalize version.

✅ Post-merge checklist

• Create a release.