Update js_locale_helper.rb

Fix "undefined method `end_with?' for 1:Fixnum" when field name in YML file is not quoted number like:

```
    user_action_groups:
      1: "Likes Given"
      2: "Likes Received"
```

(yamllint.com validates such file as valid YML file)
Merge pull request #976 from abbat/patch-1

Update js_locale_helper.rb