xdgshellclient: fix initial placement with maximize

BUG: 439986


(cherry picked from commit ef894f34)

src/workspace.cpp

@@ -784,7 +784,7 @@ void Workspace::addShellClient(AbstractClient *client)
         if (client->isRequestedFullScreen()) {
             placementDone = true;
         }
-        if (client->maximizeMode() == MaximizeMode::MaximizeFull) {
+        if (client->requestedMaximizeMode() == MaximizeMode::MaximizeFull) {
             placementDone = true;
         }
         if (client->rules()->checkPosition(invalidPoint, true) != invalidPoint) {

src/xdgshellclient.cpp

@@ -369,6 +369,7 @@ XdgToplevelClient::XdgToplevelClient(XdgToplevelInterface *shellSurface)
         setOnActivities({a->current()});
     }
 #endif
+    move(workspace()->activeOutput()->geometry().center());
 
     connect(shellSurface, &XdgToplevelInterface::windowTitleChanged,
             this, &XdgToplevelClient::handleWindowTitleChanged);