Add IT for process with signal BPMN events

With the implementation of signal BPMN events, we should ensure that Optimize has an IT that imports data from a process containing such events.

The implementation tasks are here (there might be more):

• https://github.com/camunda/product-hub/issues/656
• https://github.com/camunda/product-hub/issues/142

The newsymbols are:
"signalStartEvent",
"signalStartInterruptingSubProcessEvent",
"signalStartNonInterruptingSubProcessEvent",
"signalIntermediateCatchEventAttachedToEventBasedGateway",
"signalIntermediateThrowEvent",
"signalIntermediateCatchEvent",
"signalIntermediateBoundaryInterruptingEvent",
"signalIntermediateBoundaryNonInterruptingEvent",
"signalEndEvent"
 
 
ATs:

• Optimize has tests to ensure compatibility for importing signal events
• These tests are only run when testing against versions of Zeebe that support these events

Testing Notes:

• Focus on the UI testing, by deploying a process containing a signal start event (eg attached example process), using data from such a process in a report and confirming correct heatmap display
• Test process is attached and works as follows:
  • deploy the process 
  • broadcast signal with name "startSignalName" to start the process
  • wait until instance reaches signalProcessServiceTask1 
  • broadcast signal with name "nonInterruptingBoundarySignal"
  • wait until instance reaches signalProcessServiceTask2
  • broadcast signal with name "interruptingBoundarySignal"
  • wait until signal reaches eventBasedGateway
  • broadcast signal with name "eventBasedGatewaySignal"

Notes:

• Can https://github.com/camunda/camunda-optimize/issues/6911 be implemented at the same time? --> doesnt look like it