APISite.unconnected_pages: Require WikibaseClient instead of "Wikibase Client"
APISite.unconnected_pages: Require WikibaseClient instead of "Wikibase Client"

Bug: T198454
Change-Id: Ied4d807f127eb94297a666ac4eb5dea507ed8411

wikimedia/pywikibot-core,wikimedia/pywikibot-core,PersianWikipedia/pywikibot-core