[AXON-46] chore: add unit tests for auth strategies

[sdzh-atlassian]

What is this?

When working on the other auth stuff, I've come to the point of doing a pretty big change around strategy.ts

To minimize the risk of breaking thing, I'm first creating a bunch of unit tests for the existing logic with minimal changes.

The original plan was to literally touch nothing and only add tests, however there are some small necessary changes:

• encryption-related stuff is moved out of strategy.ts to a separate file strategyCrypto.ts - primarily because it caused issues with jest for some reason
• created trivial functions for verifier and basic auth
• bumped @types/jest version and added @jest/globals to resolve the weird it.each issue

Despite lots of logic, these things are effectively data classes, so I'm only testing the happy path to make sure the output doesn't change accidentally down the line

How was this tested

• npm run test # OK
• Ran authentication to Jira and BB-prod

[bwieger-atlassian-com]

LGTM, and we can use this dashboard to track if this has negative impact: https://app.amplitude.com/analytics/atlassian/chart/z676btcj