[SP-1322]: Backport of PDI-12155 - Error when saving a transformation with MongoDB Output step into Kettle Database Repository (5.1)

There are unit tests for the fix.
[SP-1322]: Backport of PDI-12155 - Error when saving a transformation with MongoDB Output step into Kettle Database Repository (5.1)

There is a fix.
Merge pull request #72 from TatsianaKasiankova/SP-1322

SP-1322  Backport of PDI-12155 - Error when saving a transformation with MongoDB Output step into Kettle Database Repository (5.1)