Bug 1040271 - [L10n][SMS] Clean up mozL10n.get uses in SMS app

since the unlocalised text is passed to the localiser as a string and not separate pieces of data, it should not cause any inconsistencies.

However, Pike has pointed out that the list separators would no longer be localised. Since there is nothing in place to localise a list of strings (AFAIK), I think we have to manually do it - see the first solution in these comments.