The TermInLangIdsResolver service in SingleEntitySourceServices should be migrated to the new service wiring files in repo and client respectively. This will allow us to stop passing a SingleEntitySourceServicesFactory into PrefetchingTermLookupFactory, and will finally allow us to remove the SingleEntitySourceServiceFactory service (T277731).
TermInLangIdsResolver is bound to one entity source, so the service we migrate should be a kind of TermInLangIdsResolverFactory, which is given an entity source (or its database name?) and returns a TermInLangIdsResolver.