[olm] implement tests to new error messages & message order

Summary:
Tests for https://github.com/CommE2E/olm/pull/12 and https://github.com/CommE2E/olm/pull/11.

After PRs are merged and the olm release is made I'll update the package.json file to the propper version and publish this diff for review.

Test Plan: Run tests

Reviewers: ashoat

Reviewed By: ashoat

Subscribers: tomek

Differential Revision: https://phab.comm.dev/D11314