[REQUIRED] Environment info

firebase-tools: 9.1.2

Platform: macOS

[REQUIRED] Test case

see steps to reproduce

[REQUIRED] Steps to reproduce

firebase init
-> Select "Emulators: Set up local emulators for Firebase features"
-> Select "Don't set up a default project"
-> Select "Firestore Emulator"
Would you like to enable the Emulator UI? (Y/n)
-> Select Y

now launch emulator with
firebase emulators:start

[REQUIRED] Expected behavior

One would expect that the Emulator UI would start without a default project or at least give a warning or error why the emulator UI has not started.

[REQUIRED] Actual behavior

You only see a message "Emulator Hub not running".

All emulators ready! It is now safe to connect your app.

┌───────────┬────────────────┐
│ Emulator │ Host:Port │
├───────────┼────────────────┤
│ Firestore │ localhost:8080 │
└───────────┴────────────────┘
Emulator Hub not running.
Other reserved ports: