In the context of dashboard filters, we are adding variable filters to multiple reports. In OPT-3585 we added the ability to add filters to the report. While some incompatibilities are already taken care of (e.g. instance state filter for dmn report). We need to extend this check to variable filters too, so that:

• a variable filter for a report is only applied if the variable exists for the process definition of that report
• if necessary, we could cache the available variable names for a given report to avoid to lookup on each evaluation