Vaccine changes: possible NPE fix

Author: KarnaiahPesula

sormas-ui/src/main/java/de/symeda/sormas/ui/vaccination/VaccinationEditForm.java

@@ -104,7 +104,7 @@ protected void addFields() {
 		vaccineName.addValueChangeListener(e -> {
 			Vaccine vaccine = (Vaccine) e.getProperty().getValue();
 			if (vaccine != null) {
-				vaccineManufacturer.setValue(vaccine.getManufacturer().get());
+				vaccineManufacturer.setValue(vaccine.getManufacturer().isEmpty() ? null : vaccine.getManufacturer().get());
 
 				// VaccineType
 				if (vaccine.getVaccineType().isPresent()) {