refactor(core): Extract ActiveWebhooks out of ActiveWorkflowRunner (no-changelog) (#8171)

## Summary
This PR continues refactoring webhooks code for better modularity.
Continued from #8069 to bring back `ActiveWebhooks`, but this time
actually handling active webhook calls in this class.

## Review / Merge checklist
- [x] PR title and summary are descriptive

packages/cli/test/unit/webhooks.test.ts

@@ -4,7 +4,7 @@ import { mock } from 'jest-mock-extended';
 
 import config from '@/config';
 import { AbstractServer } from '@/AbstractServer';
-import { ActiveWorkflowRunner } from '@/ActiveWorkflowRunner';
+import { ActiveWebhooks } from '@/ActiveWebhooks';
 import { ExternalHooks } from '@/ExternalHooks';
 import { InternalHooks } from '@/InternalHooks';
 import { TestWebhooks } from '@/TestWebhooks';
@@ -22,7 +22,7 @@ describe('WebhookServer', () => {
 
 	describe('CORS', () => {
 		const corsOrigin = 'https://example.com';
-		const activeWorkflowRunner = mockInstance(ActiveWorkflowRunner);
+		const activeWebhooks = mockInstance(ActiveWebhooks);
 		const testWebhooks = mockInstance(TestWebhooks);
 		mockInstance(WaitingWebhooks);
 		mockInstance(WaitingForms);
@@ -36,7 +36,7 @@ describe('WebhookServer', () => {
 		});
 
 		const tests = [
-			['webhook', activeWorkflowRunner],
+			['webhook', activeWebhooks],
 			['webhookTest', testWebhooks],
 			// TODO: enable webhookWaiting & waitingForms after CORS support is added
 			// ['webhookWaiting', waitingWebhooks],