Change Details

Once T312223 has hopefully removed all uses of `LanguageFallbackLabelDescriptionLookupFactory` in favor of the new `FallbackLabelDescriptionLookupFactory`, remove the old factory. Based on [codesearch](https://codesearch.wmcloud.org/search/?q=LanguageFallbackLabelDescriptionLookupFactory&i=nope&files=&excludeFiles=&repos=) this would mean to make sure that this class is removed from at lest the following repositories: [ ] Math [ ] WikibaseCirrusSearch [ ] ArticlePlaceholder [ ] WikibaseLexemeCirrusSearch [ ] WikibaseLexeme [ ] Wikibase

Once T312223 has hopefully removed all uses of `LanguageFallbackLabelDescriptionLookupFactory` in favor of the new `FallbackLabelDescriptionLookupFactory`, remove the old factory. Based on [codesearch](https://codesearch.wmcloud.org/search/?q=LanguageFallbackLabelDescriptionLookupFactory&i=nope&files=&excludeFiles=&repos=) this would mean to make sure that this class is removed from at lest the following repositories: [x] Math [x] WikibaseCirrusSearch [ ] ArticlePlaceholder [ ] WikibaseLexemeCirrusSearch [ ] WikibaseLexeme [ ] Wikibase

Once T312223 has hopefully removed all uses of `LanguageFallbackLabelDescriptionLookupFactory` in favor of the new `FallbackLabelDescriptionLookupFactory`, remove the old factory. Based on [codesearch](https://codesearch.wmcloud.org/search/?q=LanguageFallbackLabelDescriptionLookupFactory&i=nope&files=&excludeFiles=&repos=) this would mean to make sure that this class is removed from at lest the following repositories: [ x] Math [ x] WikibaseCirrusSearch [ ] ArticlePlaceholder [ ] WikibaseLexemeCirrusSearch [ ] WikibaseLexeme [ ] Wikibase