PubSub Emulator on Windows launches a Java window

### [REQUIRED] Environment info

**firebase-tools:** 9.3.0

**Platform:** WIndows 10

### [REQUIRED] Test case

I've been using the Firestore, Functions, and Hosting emulators for ~1 year now. Today I added a PubSub function which means I had to start using the `pubsub` emulator.

For some reason when I do `emulators:start` the PubSub emulator launches in a new window:

This doesn't affect any of the functionality except that when I do `Ctrl^C` to close the `emulators:start` process it does **not** close the PubSub emulator. I have to manually click to close that window in order to free up the port.

### [REQUIRED] Steps to reproduce

As far as I can tell, just launching the PubSub emulator on Windows.

### [REQUIRED] Expected behavior

PubSub emulator runs as an invisible subprocess just like Functions, Firestore, etc.

### [REQUIRED] Actual behavior

See above.

No source files, tests, or entry points are named. Reproduce `emulators:start` with the PubSub emulator on Windows 10, then trace how the CLI starts and stops that emulator; done means it runs invisibly and closes with the parent process on Ctrl+C.

Written by the indexing model from the issue text.