Context:

In a recent PR we noticed that we seem to be missing some validation iIn ValidationHelper.validateProcessFilters.
For example, we only validate that either start or end field of any StartDateFilters are not null, when this actually only applies to fixedDateFilters - rolling and relative filterts should always have start be nonNull. We also don't have any validation for EndDateFilters and FlowNodeDurationFilters (here I am assuming the map can be empty, but if it's not empty then each DurationFilterDataDto has fields that should be nonNull).

AT:

• Evaluate adding more validation to existing report filters (the ones mentioned above as well as others, not sure the above is complete)
• Potentially also add IT  for the new validation