luci: optimize the backup and restore page

luci-app-passwall2/luasrc/model/cbi/passwall2/client/log.lua

@@ -16,9 +16,9 @@ s = fb:section(SimpleSection, translate("Backup and Restore"), translate("Backup
 							"<br><font color='red'>" ..
 							translate("Note: Restoring configurations across different versions may cause compatibility issues.") ..
 							"</font>")
-o = s:option(DummyValue, '', nil)
-o.template =  appname .. "/log/backup_restore"
 
+s.anonymous = true
+s:append(Template(appname .. "/log/backup_restore"))
 
 local backup_files = {
     "/etc/config/passwall2",

luci-app-passwall2/luasrc/view/passwall2/log/backup_restore.htm

@@ -2,7 +2,6 @@
 local api = require "luci.passwall2.api"
 -%>
 
-<%+cbi/valueheader%>
 <div class="cbi-value" id="_backup_div">
     <label class="cbi-value-title"><%:Create Backup File%></label>
     <div class="cbi-value-field">
@@ -131,4 +130,3 @@ local api = require "luci.passwall2.api"
 		}
 	}
 </script>
-<%+cbi/valuefooter%>