pk: no need to fetch the details of the updatable packages

When the details are required, they'll be requested. This way we don't
fetch the updatable packages updates when the user just wants to find an
app.

CCBUG: 432657

libdiscover/backends/PackageKitBackend/PackageKitBackend.cpp

@@ -704,7 +704,6 @@ void PackageKitBackend::getUpdatesFinished(PackageKit::Transaction::Exit, uint)
 {
     if (!m_updatesPackageId.isEmpty()) {
         resolvePackages(kTransform<QStringList>(m_updatesPackageId, [](const QString &pkgid) { return PackageKit::Daemon::packageName(pkgid); }));
-        fetchDetails(m_updatesPackageId);
     }
 
     m_updater->setProgressing(false);