Bug 1080169 - Update test_sms_with_attachments.py to correlate with the ...

...manual test


As the steps are different I added a new test instead of changing the existing one
The class name is the same as another [test]. I suggest to rename it to something else.

[test]:https://github.com/mozilla-b2g/gaia/blob/master/tests/python/gaia-ui-tests/gaiatest/tests/functional/messages/test_sms_with_attachments.py#L11