De-duplicate checkMissingTransitions methods #885
Description
NodeService.checkAndFixMissingTransitions() and TrainrunSectionService.checkMissingTransitionsAfterDeletion() methods are very close, but don't do the same thing. This code duplication made a bug very difficult to detect in this PR: b42f4e9
I suggest to de-duplicate this code and spread the use of a single method.