Fix the definition of new issue in validate job
Fix the definition of new issue in validate job

In validate job, an issue is considered as new, if there is no
existing valid issue in the collection with the same unique id.

renatahodovan/fuzzinator,akosthekiss/fuzzinator,renatahodovan/fuzzinator,akosthekiss/fuzzinator,renatahodovan/fuzzinator,akosthekiss/fuzzinator,renatahodovan/fuzzinator,akosthekiss/fuzzinator