fix(oncall-api): return all users from lowest escalation level

[brianphillips]

Description

Instead of return all users that match the escalation level of the first user returned in the oncall list, return users that match the lowest escalation level. Previously, if a higher escalation level user was the first item in the array, only users at that same level would be returned.

Issue number: Fixes PagerDuty/backstage-plugin-backend#34

Type of change

• [ ] New feature (non-breaking change which adds functionality)
• [x] Fix (non-breaking change which fixes an issue)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• [x] I have performed a self-review of this change
• [x] Changes have been tested
• [ ] Changes are documented
• [x] Changes generate no new warnings
• [x] PR title follows conventional commit semantics

If this is a breaking change 👇

• [ ] I have documented the migration process
• [ ] I have implemented necessary warnings (if it can live side by side)

Acknowledgement

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

Disclaimer: We value your time and bandwidth. As such, any pull requests created on non-triaged issues might not be successful.

[brianphillips]

@t1agob could you take a look at this please?

[t1agob]

Hi @brianphillips. Thanks for submitting this PR. I have tested it and it doesn't change the overall behaviour of the API and fixes the issue of not showing the ordered items.

Approved! I have changed the base branch to comply with our guidelines. I'll work on merging this to main and release a new version shortly.