Vue tests & linting

[roblevintennis]

When we ported agnostic-vue to Vue 3 + Vite, we didn't yet address:

• Linting issues
• Tests

This task is to fix all that.

Also, we'll need to add back yarn test:vue to the top-level monorepo's package.json script:

    "test": "yarn sync:react && yarn test:react && yarn sync:vue && yarn sync:svelte && yarn test:svelte",

See https://github.com/AgnosticUI/agnosticui/blob/master/package.json#L41

[roblevintennis]

I got the Eslint working and cleaned up the files.

For testing, Jest and Vite seems to be a shit show. Will rewvisit specs using idiomatic vite/vue 3 way.

vitejs/vite#1955