fix: download/selector issue, eslint errors, rework multi select flow

[jeffzyliu]

Description

deploy preview: https://deploy-preview-633--pine-beetle-prediction-dev.netlify.app/ multi select is implemented weird--basiclaly none selected is the same as all. I chose to make all selected the default now.

Type of Change

• [ ] New feature
• [x] Bug fix
• [ ] Breaking change
• [ ] Documentation update

Checklist

• [ ] Unit/integration tests
• [ ] Documentation

Tickets

• closes #629

Screenshots

Please attach any design screenshots if UI update.

[jeffzyliu]

need to replace this with an actual x icon, then get rid of the clear button and add a special clear selections button to the download modal