Stats Widgets: localize display names

[ScoutHarris]

Ref #12702

This localizes the Stats Widgets display names.

To test:
Since there aren't localizations yet (obviously), you can verify the widgets are using localized strings by altering the CFBundleDisplayName in their respective InfoPlist.strings file.

The CFBundleDisplayName is displayed:

• In the widget list.
• In the widget title.

Example with altered CFBundleDisplayName:

PR submission checklist:

• I have considered adding unit tests where possible.

• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[peril-wordpress-mobile]

You can trigger an installable build for these changes by visiting CircleCI here.

[bjtitus]

I was able to reproduce the title change when changing the string from the InfoPlist.strings files.