Firebase Hosting Channels with multiple targets are not all authorized in auth

When deploying a project with multiple hosting target to Hosting Channels, only one of the target is added as a Firebase Authentication authorized domain.

### [REQUIRED] Environment info

**firebase-tools:** 9.1.1
**Platform:** MacOS

### [REQUIRED] Test case

### [REQUIRED] Steps to reproduce

1. Create a firebase project
2. Configure multiple hosting target for it
3. Deploy a channel

### [REQUIRED] Expected behavior

All auth target, or a specified one are being added as Authentication authorized domain.

### [REQUIRED] Actual behavior

Only one is added. In my case I have 3 Hosting target, and the one being added is the second one.