Make FIREBASE_FRAMEWORKS_VERSION injectable for testing (#6571)

* Make FIREBASE_FRAMEWORKS_VERSION injectable for testing

When `internaltesting` experiment is enabled, the value for
`FIREBASE_FRAMEWORKS_VERSION` shall be derived from the environment
variable with the same name.

This is only intended for testing purposes. Code behavior for
production does not change.

---------

Co-authored-by: James Daniels <jamesdaniels@google.com>

src/frameworks/constants.ts

@@ -1,5 +1,6 @@
 import { SupportLevel } from "./interfaces";
 import * as clc from "colorette";
+import * as experiments from "../experiments";
 
 export const NPM_COMMAND_TIMEOUT_MILLIES = 10_000;
 
@@ -25,7 +26,10 @@ export const FEATURE_REQUEST_URL =
   "https://github.com/firebase/firebase-tools/issues/new?template=feature_request.md";
 export const MAILING_LIST_URL = "https://goo.gle/41enW5X";
 
-export const FIREBASE_FRAMEWORKS_VERSION = "^0.10.4";
+const DEFAULT_FIREBASE_FRAMEWORKS_VERSION = "^0.10.4";
+export const FIREBASE_FRAMEWORKS_VERSION =
+  (experiments.isEnabled("internaltesting") && process.env.FIREBASE_FRAMEWORKS_VERSION) ||
+  DEFAULT_FIREBASE_FRAMEWORKS_VERSION;
 export const FIREBASE_FUNCTIONS_VERSION = "^4.3.0";
 export const FIREBASE_ADMIN_VERSION = "^11.0.1";
 export const SHARP_VERSION = "^0.32.1";