[scripting] Make panels() not return the desktops() containments

It was filtering by isPanel() before port to QJSEngine:
033ad5ca

BUG: 435081

shell/scripting/scriptengine_v1.cpp

@@ -485,8 +485,10 @@ QJSValue ScriptEngine::V1::panels() const
     const auto result = m_engine->m_corona->containments();
 
     for (const auto c : result) {
-        panels.setProperty(count, m_engine->wrap(c));
-        ++count;
+        if (isPanel(c)) {
+            panels.setProperty(count, m_engine->wrap(c));
+            ++count;
+        }
     }
     panels.setProperty(QStringLiteral("length"), count);