Remove use strict in extensions (part 2)

We compile using alwaysStrict so this directive is not needed

extensions/css-language-features/server/src/cssServerMain.ts

@@ -2,7 +2,8 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *  Licensed under the MIT License. See License.txt in the project root for license information.
  *--------------------------------------------------------------------------------------------*/
-'use strict';
+
+
 
 import {
 	createConnection, IConnection, TextDocuments, InitializeParams, InitializeResult, ServerCapabilities, ConfigurationRequest, WorkspaceFolder