Bug 1070731 - [sms] unit test refactoring for new version chai.assert api

test_agent used very old version chai library version=0.5.3
in the current version=1.9.1 deepEqual take prototype into consideration

apps/sms/test/unit/localization_helper_test.js - plain structure
nit: could you please fix argument alignment here and below?
```
assert.lengthOf(
  ThreadUI.container.querySelectorAll('[data-message-id="23"]'),
  1
);
```