Prevent possible crash when showing results for other languages

[cooltey]

What does this do?

Fix a possible crash when showing results for other languages in the SearchResultsFragment

Why is this needed?

We get the language code by providing a position to the language list, which may cause a crash.

val langCode = WikipediaApp.instance.languageState.appLanguageCodes[position]

This PR changes the plain list to a Pair<> that contains the language code with its result counts.

The error log in console

https://play.google.com/console/u/1/developers/6169333749249604352/app/4976363884102945010/vitals/crashes/0e0fb84f88cb64408c0412acfb8550ff/details?days=28&versionCode=50501&isUserPerceived=true