Firebase emulators should impose HTTP/2 request/response size limits

### [REQUIRED] Environment info

**firebase-tools:** 8.14.1

**Platform:** macOS

### [REQUIRED] Test case

Write a function that proxies a large file (10MB+) by piping the data to the firebase cloud function response stream.

### [REQUIRED] Steps to reproduce

Call the test function and verify that your 10MB+ file is downloaded successfully.

### [REQUIRED] Expected behavior

The download should be cut-off at 10MB with a "response error" as this is the request/response size limit imposed by firebase quotas (see https://firebase.google.com/docs/functions/quotas)

### [REQUIRED] Actual behavior

This file will be proxied by the emulator in full without any request/response size limitation. This means the app will behave differently in local development (emulator) compared to the final product deployed to Firebase.