Add e2e CLI test for `blitz new`

### What do you want and why?

We currently have [a few `blitz new` tests](https://github.com/blitz-js/blitz/blob/canary/packages/cli/test/commands/new.test.ts), but not a complete e2e test for the new app.

We want to:

1. Test the following for each form option
2. Test `blitz build` success inside new app
3. Test `yarn test` success inside new app
1. Need to remove the `.skip` from `app/pages/index.test.tsx` to ensure that test passes
4. Test `yarn lint` has no errors or warnings
5. Start app (use `blitz start --production` since we already ran `blitz build` above)
6. Test user sign up
7. Test user log out
8. Test user duplicate email signup (correct message displayed)
8. Test user log in

### Possible implementation(s)

Add Cypress to our CLI testing setup. See the [Redwood CLI cypress test](https://github.com/redwoodjs/redwood/blob/c0980353d5726e37c55c4f01cc3bbfa4b5ef268e/tasks/e2e/cypress/integration/tutorial/tutorial.js) for a great example/starting point.

### Other

You don't have to add all the above tests in one PR. You can just add as much as you have time/energy for. First person needs to add cypress and very basic initial test.