fix import

Author: JonasBa

packages/core/test/lib/base.test.ts

@@ -1,6 +1,6 @@
 import { Hub, Scope, Session } from '@sentry/hub';
 import { Event, Span, Transport } from '@sentry/types';
-import { logger, SentryError, SyncPromise, dsnToString } from '@sentry/utils';
+import { logger, SentryError, dsnToString } from '@sentry/utils';
 
 import * as integrationModule from '../../src/integration';
 import { TestBackend } from '../mocks/backend';