don't check for panel visible during startup

if any kscreen related activities occurred
during startup, the panel wouldn't be visible
yet, and this would assert. This often happens
when a screen gets disabled at startup

CCBUG:377280

shell/panelview.cpp

@@ -116,6 +116,7 @@ PanelView::~PanelView()
 
 KConfigGroup PanelView::panelConfig(ShellCorona *corona, Plasma::Containment *containment, QScreen *screen)
 {
+    qWarning()<<"AAAA"<<containment<<screen;
     if (!containment || !screen) {
         return KConfigGroup();
     }

shell/shellcorona.cpp

@@ -787,7 +787,11 @@ void ShellCorona::screenInvariants() const
         foreach (const PanelView *panel, panelsForScreen(screen)) {
             Q_ASSERT(panel->containment());
             Q_ASSERT(panel->containment()->screen() == id || panel->containment()->screen() == -1);
-            Q_ASSERT(panel->isVisible());
+            //If any kscreen related activities occurred
+            //during startup, the panel wouldn't be visible yet, and this would assert
+            if (panel->containment()->isUiReady()) {
+                Q_ASSERT(panel->isVisible());
+            }
         }
 
         screens.insert(screen);