Fix services imports

packages/services/test/src/utils.spec.ts

@@ -1,7 +1,7 @@
 // Copyright (c) Jupyter Development Team.
 // Distributed under the terms of the Modified BSD License.
 
-import expect from 'expect.js';
+import { expect } from 'chai';
 
 import { PromiseDelegate } from '@phosphor/coreutils';
 

packages/services/test/src/utils.ts

@@ -5,7 +5,7 @@ import encoding from 'text-encoding';
 
 import WebSocket from 'ws';
 
-import expect from 'expect.js';
+import { expect } from 'chai';
 
 import { UUID } from '@phosphor/coreutils';