Implement partner authentication service

[aaemnnosttv]

Feature Description

The partner services provided to the PAX app should be extended to include a new implementation for the authentication service.

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Do not alter or remove anything below. The following sections will be managed by moderators only.

Acceptance criteria

• The authenticationService of the PAX partner services should be implemented similar to others such that it is automatically provided to all PAX app instances

Implementation Brief

• Update createPaxServices to define a new top-level authenticationService with its methods
  • get returning a GetResponse, specifically just the { accessToken: string } (authUser not needed)
    Return the same token used in the config for now
  • fix returning a FixResponse; this can be the same as fixBusinessInfo for now

Test Coverage

• Add relevant coverage as for other services

QA Brief

QA:Eng

• Verify that tests are passing and nothing else is affected. Basically this can be verified in CR/MR and probably go to approval afterwards since there is nothing much to test

Changelog entry

• Add the partner authentication service to the PAX app.

[benbowler]

QA:Eng Passed ✅