Resolves: tdf#120745 - Firefox themes UI

Indent the images of the preinstalled theme

Change-Id: I9f4b250ba6eb7663e0631a983244311c08646274
Reviewed-on: https://gerrit.libreoffice.org/66583
Tested-by: Jenkins
Reviewed-by: Heiko Tietze <tietze.heiko@gmail.com>

cui/uiconfig/ui/personalization_tab.ui

@@ -64,6 +64,10 @@
                   <object class="GtkGrid">
                     <property name="visible">True</property>
                     <property name="can_focus">False</property>
+                    <property name="margin_left">24</property>
+                    <property name="margin_right">6</property>
+                    <property name="row_spacing">1</property>
+                    <property name="column_spacing">1</property>
                     <child>
                       <object class="GtkButton" id="default1">
                         <property name="can_focus">True</property>