CI: fail on test errors

[longzheng]

While debugging another issue I noticed that there is actually a test failing but the CI is reporting all good. For example the last CI run https://github.com/deepgram/deepgram-js-sdk/actions/runs/9403306912/job/25899538297#step:4:120

I saw it's because the CI is only running the npm run test:coverage which doesn't seem to throw an error if there are test errors.

I thought the easiest fix is to just run the test separately to generating the coverage.

[longzheng]

I'm not 100% sure if the test command also needs a change since currently it has || :, which I'm not sure what the original intent was.

https://github.com/deepgram/deepgram-js-sdk/blob/7ce44bdd639891b06bfde6385a815372a5122eee/package.json#L48

[lukeocodes]

This should be resolved in the latest version