Filter betatesters by betagroups

[n-a-f-i-s-a]

📝 Summary of Changes

Changes proposed in this pull request:

• Filter beta testers by beta groups

🧐🗒 Reviewer Notes

• Betatesters API doesn't support filtering by both identifier and beta groups. When we need to filter by both identifier and beta group names we need to use the betagroup endpoint with included option .app and .betatesters.

🔨 How To Test

swift run asc testflight betatesters list --filter-identifiers iba.test3 --filter-group-names testGrp1

[adamjcampbell]

Is this PR making use of the endpoint described here: https://developer.apple.com/documentation/appstoreconnectapi/list_all_beta_testers_in_a_betagroup ?

I feel like there's room for a different Operation making use of this endpoint to make some of this code easier to reason about

[n-a-f-i-s-a]

@adamjcampbell When group name and identifiers are both passed I am calling the betagroup endpoint with included beta testers

[n-a-f-i-s-a]

This is no longer required as we have #176