Removed handled option from doCatch

The handled option on doCatch is @deprecated and discourage to use. We are going to remove those in the near future. So please remove it from the IDE.

eg in the source code

        <doCatch>
            <handled>
                <language language="simple"/>
            </handled>
            <to uri=""/>
        </doCatch>

The <handled> should not be supported / possible to use.