Merge pull request #5735 from matrix-org/travis/use-strict-no

Remove a bunch of useless 'use strict' definitions

src/utils/MegolmExportEncryption.js

@@ -15,8 +15,6 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-"use strict";
-
 // polyfill textencoder if necessary
 import * as TextEncodingUtf8 from 'text-encoding-utf-8';
 let TextEncoder = window.TextEncoder;