Fix Connections deprecation warning on Qt 5.15

Adopt the correct behavior to get rid of
"QML Connections: Implicitly defined onFoo properties in Connections
 are deprecated. Use this syntax instead:
 function onFoo(<arguments>) { ... }"

src/gui/Base/HTile/HTile.qml

@@ -50,7 +50,8 @@ HButton {
     Connections {
         enabled: contextMenuLoader.status === Loader.Ready
         target: contextMenuLoader.item
-        onClosed: contextMenuLoader.active = false
+
+        function onClosed() { contextMenuLoader.active = false }
     }
 
     HLoader {