Add configuration setting that allows an extended persistence context to be propagated even if there is no JTA transaction

Earlier versions of AS, allowed an extended persistence context (XPC) to propagate, even if no JTA transaction was active during use of the XPC. With the recent fix to AS7-1663, using an XPC outside of a JTA transaction and then invoking a transactional entity manager inside of a JTA transaction, will not propagate the XPC into the new transaction.

Add a domain default setting that allows the (not used in a JTA transaction) XPC to propagate into the new transaction (on behalf of a transactional entity manager). This will only happen if the XPC is active in the call stack.