Respect integration level for all position updates

More specifically, never set a vehicle's logical position (and allocate
associated resources) if the vehicle is supposed to be ignored.

Merged-by: Martin Grzenia <martin.grzenia@iml.fraunhofer.de>

Author: swltr

opentcs-documentation/src/docs/release-notes/changelog.adoc

@@ -31,6 +31,7 @@ This change log lists the most relevant changes for past releases in reverse chr
 ** Avoid `NullPointerException` when trying to assign a vehicle to a reserved transport orders that has been removed in the meantime.
 ** Actually add given properties to newly-created plant models' visual layouts.
 ** Ensure failed transport orders in order sequences are skipped correctly.
+** Respect integration level for all updates of a vehicle's logical position.
 * Changes affecting developers:
 ** Update JUnit to 6.0.2.
 ** Update Mockito to 5.21.0.

opentcs-kernel/src/main/java/org/opentcs/kernel/vehicles/DefaultVehicleController.java

@@ -837,7 +837,7 @@ private void handleProcessModelEvent(PropertyChangeEvent evt) {
     );
 
     if (Objects.equals(evt.getPropertyName(), VehicleProcessModel.Attribute.POSITION.name())) {
-      updateVehiclePosition((String) evt.getNewValue());
+      setVehiclePosition((String) evt.getNewValue());
     }
     else if (Objects.equals(
         evt.getPropertyName(),
@@ -975,18 +975,19 @@ private void updateVehiclePose(
     vehicleService.updateVehiclePose(vehicle.getReference(), incomingPoseTransformer.apply(pose));
   }
 
-  private void updateVehiclePosition(String position) {
-    // Get an up-to-date copy of the vehicle
+  private void setVehiclePosition(String position) {
     Vehicle currVehicle = vehicleService.fetch(Vehicle.class, vehicle.getReference()).orElseThrow();
 
-    if (currVehicle.getIntegrationLevel() == Vehicle.IntegrationLevel.TO_BE_RESPECTED
-        || currVehicle.getIntegrationLevel() == Vehicle.IntegrationLevel.TO_BE_UTILIZED
-        || currVehicle.getIntegrationLevel() == Vehicle.IntegrationLevel.TO_BE_NOTICED) {
-      setVehiclePosition(position);
+    boolean acceptPosition = switch (currVehicle.getIntegrationLevel()) {
+      case TO_BE_RESPECTED, TO_BE_UTILIZED, TO_BE_NOTICED -> true;
+      // Null position values reflect resetting the position and are always accepted.
+      case TO_BE_IGNORED -> position == null;
+    };
+
+    if (!acceptPosition) {
+      return;
     }
-  }
 
-  private void setVehiclePosition(String position) {
     // Place the vehicle on the given position, regardless of what the kernel
     // might expect. The vehicle is physically there, even if it shouldn't be.
     // The same is true for null values - if the vehicle says it's not on any