"Rosetta for inactive translations" feature for the current theme

[Nao]

The change made in #487 to is no longer working with the current theme.

Example: ​https://szl.wordpress.org/ (the last release was 4.7.2) doesn't have a download button in the top banner, but it's also not showing a banner to indicate that the locale is inactive.

Reference:
​https://make.wordpress.org/community/handbook/translating/teams/inactive-translations/#inactive-locales