web-forms vue component package doesn't export types

[garethbowen]

Description

When creating the demo app in a separate repo imports from @getodk/web-forms complained about being unable to find types while @getodk/xforms-engine did not.

I think it's because

1. we're missing "types": "./dist/index.d.ts", from the package.json
2. we're missing "declaration": true from the tsconfig.json