TaskTree: Get rid of unneeded done handlers' arguments

Task-number: QTCREATORBUG-29834
Change-Id: I236dec27a292a1b006b7001d01ce620960380de9
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Marcus Tillmanns <marcus.tillmanns@qt.io>

src/plugins/coreplugin/plugininstallwizard.cpp

@@ -230,7 +230,7 @@ public:
                 m_output->append(output);
             });
         };
-        const auto onUnarchiverError = [this](const Unarchiver &) {
+        const auto onUnarchiverError = [this] {
             m_label->setType(InfoLabel::Error);
             m_label->setText(Tr::tr("There was an error while unarchiving."));
         };