fix(extension): create eventChannel after initializeApp

[cabljac]

Should fix #699

TODO:

1. create RC
2. manual test

[Copilot]

Pull Request Overview

This PR defers creation of the EventArc channel until after the Firebase Admin app is initialized by replacing the static eventChannel export with a getEventChannel() factory and updating all usages accordingly.

• Replace eventChannel import with getEventChannel() in index.ts and webhook-events.ts
• Update config.ts to provide a getEventChannel() function instead of a static export
• Adjust unit tests and environment setup to reflect renamed functions and variables

Reviewed Changes

Copilot reviewed 5 out of 6 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
functions/src/index.ts	Import and invoke getEventChannel() after initializeApp()
functions/src/handlers/webhook-events.ts	Import and invoke getEventChannel() inside HTTP handler
functions/src/config.ts	Replace eventChannel constant with getEventChannel()
functions/tests/tests/unit/handlers/webhook-events.test.ts	Mock getEventChannel() instead of eventChannel
functions/tests/helpers/setupEnvironment.ts	Rename environment-path variables to consistent camelCase

Files not reviewed (1)

• firestore-stripe-payments/functions/package-lock.json: Language not supported

Comments suppressed due to low confidence (2)

firestore-stripe-payments/functions/src/config.ts:55

• [nitpick] Add a JSDoc comment to getEventChannel describing its return type (Channel | undefined) and when it returns undefined for improved clarity.

export const getEventChannel = () => {

firestore-stripe-payments/functions/src/index.ts:21

• The default config import isn't used in this file—consider removing it to keep imports focused.

import config from './config';

[Copilot]

The default config import appears unused here; you can remove it to reduce unnecessary imports.

Suggested change

	import config, { getEventChannel, stripe } from '../config';
	import { getEventChannel, stripe, stripeWebhookSecret } from '../config';

[Copilot]

The real getEventChannel() returns undefined when EVENTARC_CHANNEL is not set; mock it to return undefined instead of null to better mirror production behavior.

Suggested change

	getEventChannel: () => null,
	getEventChannel: () => undefined,