SVGHMI: fix again appication of frequency value when given in label. Use it on PushButton instance in svghmi test.
<?xml version='1.0' encoding='utf-8'?>
<SVGHMI xmlns:xsd="http://www.w3.org/2001/XMLSchema" OnWatchdog="echo Watchdog for {name} !" WatchdogInitial="10" WatchdogInterval="5" EnableWatchdog="true" Path="{name}"/>