[libadwaita] demo: Remove the deprecated .sidebar class

[Alexander Mikhaylenko <alexm src gnome org>]

commit 217765989a426c78e9db25e8eda78b1dd97e1859
Author: Marco Melorio <marco melorio protonmail com>
Date:   Sun Oct 24 18:16:12 2021 +0200

    demo: Remove the deprecated .sidebar class

 demo/adw-demo-window.ui      | 6 +-----
 demo/adw-flap-demo-window.ui | 6 +-----
 2 files changed, 2 insertions(+), 10 deletions(-)
---
diff --git a/demo/adw-demo-window.ui b/demo/adw-demo-window.ui
index 04db9c4c..513d7442 100644
--- a/demo/adw-demo-window.ui
+++ b/demo/adw-demo-window.ui
@@ -88,11 +88,7 @@
               <object class="AdwLeafletPage">
                 <property name="navigatable">False</property>
                 <property name="child">
-                  <object class="GtkSeparator">
-                    <style>
-                      <class name="sidebar"/>
-                    </style>
-                  </object>
+                  <object class="GtkSeparator"/>
                 </property>
               </object>
             </child>
diff --git a/demo/adw-flap-demo-window.ui b/demo/adw-flap-demo-window.ui
index 90dfcfe2..75853d89 100644
--- a/demo/adw-flap-demo-window.ui
+++ b/demo/adw-flap-demo-window.ui
@@ -44,11 +44,7 @@
               </object>
             </property>
             <property name="separator">
-              <object class="GtkSeparator">
-                <style>
-                  <class name="sidebar"/>
-                </style>
-              </object>
+              <object class="GtkSeparator"/>
             </property>
             <property name="content">
               <object class="GtkStack" id="stack">