Firebase auth emulator in multi-tenant mode only exports users tied to the default tenant #5623

When using the auth emulator in a multi-tenant setup, users aren't exported or imported for any tenant other than the default tenant.

[REQUIRED] Environment info

firebase-tools: 11.24.1

Platform: macOS

[REQUIRED] Test case

1. start the auth emulator with firebase emulators:start --export-on-exit=./users --import=./users
2. Serve this file locally.
3. Follow steps to reproduce

[REQUIRED] Steps to reproduce

1. Start the auth emulator with firebase emulators:start --export-on-exit=./users --import=./users
2. Using the provided web ui with firebase auth emulator running, create a user via the Google Provider button.
3. See that the tenant is available in the tenant select dropdown in the emulator auth UI, and that the user is listed for tenant abc-123 and not the default tenant.
4. Stop the emulator via SIGINT (ctrl+c)
5. See that the exported user json file does not include the user that was available in the emulator UI.

[REQUIRED] Expected behavior

The exported users should include all users, segmented by tenant.

[REQUIRED] Actual behavior

The exported users only include users tied to the default tenant.