Safeguard LRA filters for situations when CDI is not available

When CDI is not available in LRA microservice, following exception is thrown:

Caused by: java.lang.NullPointerException
	at io.narayana.lra.filter.ServerLRAFilter.filter(ServerLRAFilter.java:311)

This is thrown because CDI is not available in the container. The check for null injection can prohibit this behavior and LRA can still function for REST-based services in case CDI is not present.