Test JS SDK exports and packaging

[hculea]

Current Behavior

#15

In the course of refactoring the JS SDK as above, there has been a point where, although all NPM linting commands were succeeding, the examples commonjs and es were not, because of misconfigured exports.

Desired Behavior

We should make sure that within the test suite, there are end-to-end tests to avoid regressions.

Benefits & Value

We would no longer rely on manual testing to detect misconfigurations such as in #15 and will be able to more confidently add such refactors.

Additional information

There has been a prior attempt to do this here:

https://github.com/1Password/onepassword-sdk-js/pull/22/files

However, this should only be used as inspiration as it is not finalized.