Once T312223 has hopefully removed all uses of LanguageFallbackLabelDescriptionLookupFactory in favor of the new FallbackLabelDescriptionLookupFactory, remove the old factory.
Based on codesearch this would mean to make sure that this class is removed from at lest the following repositories:
- Math
- WikibaseCirrusSearch
- ArticlePlaceholder
- WikibaseLexemeCirrusSearch
- WikibaseLexeme
- Wikibase