Sets the current language to specified. The parameter is the BCP47 language tag. If a language pack is not downloaded yet, spawns automatically the
AssetFile_DownloadByName() request, and sends periodic FOvrNotification_
AssetFile_DownloadUpdate to track the downloads. Once the language asset file is downloaded, call
LanguagePack_GetCurrent() to retrive the data, and use the language at runtime.