Steps to reproduce:

1. Open the attached project (pbxproject-api-test.zip)
2. Switch to iOS and make a build
3. Open Xcode project
4. Notice that 'Sign In With Apple' capability is added correctly to Unity-iPhone target
5. Try to build the Xcode project

Actual behaviour: Build will fail because AuthenticationServices.framework is added to Unity-iPhone target.
Expected behaviour: AuthenticationServices.framework that is needed by 'Sign In With Apple' capability should be added to UnityFramework target.

Notes:
This can be worked-around by adding AuthenticationServices.framework to UnityFramework target manually.
Only affects versions that have UAAL implemented (2019.3+), because before that, only one target was used.

Reproduced with:
2019.3.4f1, 2020.1.0b8