[polari] chatView: Don't use popover arrow in context menu

[Marge Bot <marge-bot src gnome org>]

commit c0857c7a1fd761c951979d5f842918e904c9bb6d
Author: Florian Müllner <fmuellner gnome org>
Date:   Wed Aug 25 00:40:12 2021 +0200

    chatView: Don't use popover arrow in context menu
    
    This matches the context popovers from GTK itself.
    
    Part-of: <https://gitlab.gnome.org/GNOME/polari/-/merge_requests/235>

 src/chatView.js | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/chatView.js b/src/chatView.js
index 6e7667cd..f6f7c5ea 100644
--- a/src/chatView.js
+++ b/src/chatView.js
@@ -841,6 +841,7 @@ export default GObject.registerClass({
             position: Gtk.PositionType.BOTTOM,
             pointing_to: new Gdk.Rectangle({ x, y }),
             menu_model: section,
+            has_arrow: false,
         });
         menu.set_parent(this._view);
         menu.popup();