Add a mouse area to allow de-focusing the unified search text field on click elsewhere

Signed-off-by: Claudio Cambra <claudio.cambra@nextcloud.com>

src/gui/tray/MainWindow.qml

@@ -238,6 +238,11 @@ ApplicationWindow {
         Accessible.role: Accessible.Grouping
         Accessible.name: qsTr("Nextcloud desktop main dialog")
 
+        MouseArea {
+            anchors.fill: parent
+            onClicked: forceActiveFocus()
+        }
+
         TrayWindowHeader {
             id: trayWindowHeader