Fix to expose missing types

[nickrttn]

Initial checklist

• I read the support docs
• I read the contributing guide
• I agree to follow the code of conduct
• I searched issues and couldn’t find anything (or linked relevant results below)
• If applicable, I’ve added docs and tests

Description of changes

This PR exposes the type declaration file in package.json, to make sure it is included in the published version of the package on NPM.

I've removed a @ts-expect-error directive in test.js where no error was being thrown by TS, except about the directive itself.

[wooorm]

Released, thanks!