chore: cleanup legacy logic (#15072)

packages/backend/server/src/app.module.ts

@@ -56,7 +56,6 @@ import { ModelsModule } from './models';
 import { CalendarModule } from './plugins/calendar';
 import { CaptchaModule } from './plugins/captcha';
 import { CopilotModule, CopilotRealtimeModule } from './plugins/copilot';
-import { CustomerIoModule } from './plugins/customerio';
 import { GCloudModule } from './plugins/gcloud';
 import { IndexerModule } from './plugins/indexer';
 import { LicenseModule } from './plugins/license';
@@ -205,7 +204,6 @@ export function buildAppModule(env: Env) {
       CaptchaModule,
       OAuthModule,
       CalendarModule,
-      CustomerIoModule,
       TelemetryModule,
       CommentModule,
       AccessTokenModule,