tdf#94037: Don't try to manipulate non-existent widget container

Regression from commit 8b779997, which replaced
named GtkFrame with GtkBox, but didn't rename the box accordingly.

Change-Id: I321dbee05faded81dbf575bca3c578ecb09f1a3e
Reviewed-on: https://gerrit.libreoffice.org/18562Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

sc/uiconfig/scalc/ui/protectsheetdlg.ui

@@ -180,7 +180,7 @@
               </packing>
             </child>
             <child>
-              <object class="GtkBox" id="box3">
+              <object class="GtkBox" id="options">
                 <property name="visible">True</property>
                 <property name="can_focus">False</property>
                 <property name="hexpand">True</property>