[applets/clipboard] Don't close when clicking history item if pop-up was pinned open by another applet

Summary:
The previous patch updates the pinned state only for the active applet. For instance, if you open the Networks applet and pin it, then switch to the Clipboard applet and click on the history item, then the Clipboard applet closes. This is because we need to use binding instead of assignment.

See https://phabricator.kde.org/D28408.

Reviewers: ngraham

Reviewed By: ngraham

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D28483

applets/systemtray/package/contents/ui/items/PlasmoidItem.qml

@@ -96,4 +96,11 @@ AbstractItem {
             preloadFullRepresentationItem(fullRepresentationItem)
         }
     }
+
+    Binding {
+        property: "hideOnWindowDeactivate"
+        value: !plasmoid.configuration.pin
+        target: plasmoidContainer.applet
+        when: null !== plasmoidContainer.applet
+    }
 }

applets/systemtray/package/contents/ui/main.qml

@@ -89,10 +89,6 @@ MouseArea {
         target: plasmoid.configuration
 
         onExtraItemsChanged: plasmoid.nativeInterface.allowedPlasmoids = plasmoid.configuration.extraItems
-        onPinChanged: {
-            if (root.activeApplet)
-                root.activeApplet.hideOnWindowDeactivate = !plasmoid.configuration.pin;
-        }
     }
 
     CurrentItemHighLight {