messaging quickstart does not work

### Step 1: Describe your environment

* Operating system: MacOS
* Browser: Safari/Chrome
* Firebase SDK version: 12.5.4

### Step 2: Describe the problem:

I have filled `config.ts` then I did `npm run build` and `firebase emulators:start`. The page loaded and I click *Request Permission* and get next output:

#### Steps to reproduce:

1. git clone https://github.com/firebase/quickstart-js
2. cd messaging/
3. fill `config.ts`
4. `npm run build`
5. `firebase emulators:start`