Fix-possible-npe-in-get-queue

[mPokornyETM]

fix #608

I can not really simulate this issues (and tries that few hours)
But when I try the steps described in #608 it works also with current release.

It might happens, that some other plugins or special settings like retention strategy,
will removed current job.
Anyway, I does not want to waste the time by finding exact scenario and just catch all exceptions as well.
That means, it does not matter, why we can not proceed the step, we will remove the item from queue and thats it.

Testing done

• Added test case as describe in the issue
• remove retry in test cases to make the tests more sensitive

Proposed upgrade guidelines

N/A

Localizations

N/A

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