applets/kicker: delete SystemEntry if it's not valid

This fixes a memory leak.

applets/kicker/plugin/systemmodel.cpp

@@ -88,7 +88,9 @@ void SystemModel::refresh()
 void SystemModel::populate()
 {
     qDeleteAll(m_entries);
+    qDeleteAll(m_invalidEntries);
     m_entries.clear();
+    m_invalidEntries.clear();
 
     auto addIfValid = [=](const SystemEntry::Action action) {
         SystemEntry *entry = new SystemEntry(this, action);
@@ -96,6 +98,8 @@ void SystemModel::populate()
 
         if (entry->isValid()) {
             m_entries << entry;
+        } else {
+            m_invalidEntries << entry;
         }
 
         QObject::connect(entry, &SystemEntry::isValidChanged, this, &AbstractModel::refresh, Qt::UniqueConnection);

applets/kicker/plugin/systemmodel.h

@@ -35,4 +35,5 @@ private:
     void populate();
 
     QVector<SystemEntry *> m_entries;
+    decltype(m_entries) m_invalidEntries;
 };