Refactors google translate integration

Google Translate Widget Dropdown only display mode added in
https://github.com/codeforamerica/ohana-web-search/pull/540 appears to
have been inadvertently removed. This commit re-sets the dropdown mode
to dropdown only.
Instead of adding this conditional, you can just add `try` on line 4, like this:
```
- SETTINGS[:language_links].try(:each) do |language_plus_code|
```