Don't show the "Web Search" action in the media context menu

All this does is try to web search for the filename of the image, which
is useless. Let's hide it entirely in this case.

src/qml/FileDelegateContextMenu.qml

@@ -32,6 +32,9 @@ DelegateContextMenu {
      */
     required property var progressInfo
 
+    // Web search isn't useful for images
+    enableWebSearch: false
+
     /**
      * @brief The main list of menu item actions.
      *